Archive of ‘Grade 11’ category
This week in Pre-Calc, I didn’t understand how to solve quadratic systems of equations algebraically. As I was going through the notes trying to understand how to do it, I practiced a question, following all the directions, and got the wrong answer. I tried every possible correction to try and get it right, but I just couldln’t seem to do it. I re-read over the question and through my steps, checking the steps in the notes to make sure that the order was right, only to realise, that I forgot to carry down a negative symbole on one of the numbers in the equation. I would like to take a moment to remind myself how important it is to revise your work as you are solving an equation, to be sure that you did not make any mistakes that could be fixed, like this one, and to pay attention to the little details and to what you are doing in an equation. Today, I will be explainning how to solve a linear equation algebraically.
First, you put the first equation into the second equation (where the “y” is in the second equation, since the first equation is equal to “y”). After you have done this, you simplify the equation, first by foiling the equation, and then by making it equal to zero. After you have done this, you factor the equation. Once you have the factor of the equation, you are able to put those points into the the first equation where “x” was. After you have put both points into the first equation (seperatly), you now have the second points for both numbers. Your first point will be the first number you got from factoring the equation, and the first nunber you got from putting that number as “x” into the first equation. The same will be for your second point of the equation.
This week in Pre-Calc, I have been trying very hard to understand the conecpts we have been learning. However, there are a few different things that I will explain.
First, when you are solving a linear equation, you want to isolate for “x”, and when it is a quadratic equation you want to isolate for “y”. To solve a linear equation, the first step is to seperate the numbers from the numbers with variables (“x”). After you have put both numbers on the other side of the less than or greater than sign, you find what the answer is to both of the numbers on the other side. Once you have done this, you divide both sides of the equation by the number in front of the variable. Once you have done this, you have the point or points that you will use. After, you put the point or points on a number line, and choose two ( one point) or three (two points) test points to determine which way works for the equation. If you are solving a quadratic equation, you could first find the factors for the equation, and write (x + 3) (x – 2). Once you have done this, you take the first number from the original equation, and would divide both numbers in the brackets by this number. Once you have done this, you take the answer that you get from dividing and flip the symbols of both numbers and use these as the points for the number line. Once you have put them on a number line, you choose three test points, and you can determine this way which parts of the number line work for the equation.
This week in Pre-Calc, I struggled with understanding how to solve quadratic inequalities, so here is how to do them.
First, you factor the equation. Next, you take the two numbers that will be used to factor and write them in two separate brackets next to “x”. Next, you take the first number from the original equation, and use that as the bottom number of a fraction of each number next to “x” in each bracket. After, you simplify the fractions, and if the number is still in fraction form, then you take the bottom number and put it in front of the “x” in the bracket, because you cannot have it in fraction form. Next you take the numbers next to “x” and give them the opposite sign that they originally had (positive or negative) and then you use those numbers, however if one or both of the numbers was a fraction, then you would put it back into it’s simplified (if possible) fraction form, and still reverse the original sign that it had, as you did with the other number. After, you put both numbers on a number line. You would use a closed circle if it is not = to zero (greater or lesser), or an open circle if it is = to zero (greater or lesser). Once both numbers are placed on the number line, you choose one number in each section (left, middle and right) of the numbers, and test them by plugging them into the equation that you created, and then you are able to determine which sections work with the equation, and therefore determine which numbers are greater, lesser or equal to “x”.
Today I am going to explain how to word problems. This is something that I have had trouble with this week, so I am going to give some tips that I have learned to help.
First, every word problem wants you to create two equations from it’s poblem. These two equations will be what you use to solve the problem. From these equations, you will create a quadratic equation. Then, you will use that equation to solve the problem. Next, if the equation is asking you about people and money (or two different things) you would put people with people and money with money in your equation. Then, like the last one you will turn this equation into a quadratic equation by using FOIL and add all the like terms together to give you a quadratic equation that you will use to solve the question.
This week, I had trouble creating and knowing how to make the “x” and “y” table of values from an equation, and knowing how to graph it.
If you had y = 2x^2 + 8x + 6 you would begin by finding the vertex. You would do that by factoring out 2 from the equation (because that is the value of the first number). So the equation would now become y = 2 (x^2 + 4x + 3) The next step would be to take the 4 divide it by two and then square it. Then, you would take that number (4) and create a zero pair after the 4x in the equation. The equation would now becomre y = 2 (x^2 + 4x + 4 – 4 +3). Then you put brackets around the first three numbers of the equation, y = 2 (x^2 + 4x + 4)(-4 +3). After this, you would go back to the number that you had to divide by two and then square (4), and root it, which gives you two. So the equation would now become, 2 (x + 4) (x + 4 ) (-1), which would become 2 (x + 4)^2 (-1). This would give you your vertex of (-4, -1). Once you have found your vertex, you are able to put it into the middle of the table, and move up by two, and down by two. The top number on the “y” values of your table will be the same on the top and bottom. These will give you your points for your graph. Once you have these you will be able to plot them on the graph, which you can draw based on where you points on (move the graph higher or lower). That is how you find the vertex, points, and graph an equation.
For this chapter in math, I have struggled. However, I learned a trick that can help make long factoring questions faster and more clear.
For these types of questions, you can substitute what’s in the brackets on both sides for a variable. If they are both the same then you can make the the same variable (a) and if they are both different you can make them different variables (a and b). After, you re-write the equation with the variables in place of what was in the brackets. After this, you can factor it. In this equation, the root of 49 is 7, so you write 7 on both sides of the equation, since the variables are squared you put an “a” next to the 7. Next, you root 9, which is three. Since three is negative, one three on a side will be negative, and the other three will be positive in the other brackets. You would do that same as the “a” and put the “b” variable next to both threes. Once youo do this, you re-write the equation replacing what the variables where for what was originally in the brackets. After, you factor what your equation is. You would factor the number that is in front of the brackets to the brackets in front of it. After you so this, you are left with your answer.
This week in math I have had some trouble figuring out some of the different strategies for factoring. I will explain how to factor using the completing the square technique.
For this example, the first thing you do is add a zero pair at the end f the equation but before the equal sign, in this equation that was +16 and – 16. Then, you take take the first three terms as your equation to solve first. To do this, you take the second term, and half it, and then square it, in this equation that was 8. Next you take one of the answer you get from that, half all of the equation (only the first three terms), and write them out next to each other (which can be simplified by writing it once and squaring it), adding on the rest of the equation that we where ignoring before. Next, you want to isolate x. To do this, you first have to take away what is not in the brackets first. In this equation, that is -6 (you would add +6 to both sides of the equation). Next, you have to get rid of the square, and to do that youo would root both numbers of both sides of the equation. When you root the other side of the equation, it becomes +-. Since the square and brackets are now gone, you can isolate the x. In this equation, you moved the four to the other side of the equation by adding -4 on both sides. This, would give you the answer.
This week, I was away from a lesson we did. After asking a few people, none seemed to have any notes. One of the many things that I learned this week, is that you can ask Mrs. Burton for the notes, if you can’t find any. Because of this, I was very confused for this lesson on how to do anything. One of the things I was most confused with though, was solving an equation. To better understand how, the “gift” technique.
For this equation, the seven is in front of the root. This can be thought of as a bow on top of a gift, you need to take it off before you can “open” any of the rest of the equation. To do this, you have to divide both sides by seven to get rid of it. Next, you have to get rid of the root or the “wrappping”. To do this, you have to square both sides. After you have done this, you have one last step to get to the “gift” (to isolate x). You have to get rid of the number that is next to the x. To do this, you divide both sides by two (or the number that is there). And this will give you your gift, or your answer.
This week, I’ve had a lot of trouble with the math. I’m stilll trying to uderstand how to do each question, but I have figured out a mistake that I need to work on correcting and understanding. I need to remember to simplify my equations after I have written them out (completing the BEDMAS part of the question).
To be able to simplify these equations, a tip I learned is to put a 1 in front of each root (unless there is already a number there) in order to make simplifying and combining like terms more clear. After having done this, you can begin simplifying and combining the question. In the picture above, 1 root 25 became root 5, because 5 x 5 is 25, times 1 (because of the number you put in front of the root), which is five. For root four, you multiply the root by the number in front of the root (1) by the number in the root (4), to get 4. When combining two like terms, the number inside the root (radical) stays the same, however, you do multiply the numbers outside the root with each other.
This week, I decided I would do my math late at night. Now, I have learned that this is not the best idea. I wanted to get it done and out of the way, however my plans doing it where quickly stopped when I came across a mistake that I made and my brain decided to not work.
After reviewing the question many times I couldn’t find an answer, so I decided to skip it and try it again the next day. Upon seeing it the next day after rest, and my brain working, I realised that the mistake was a simple subtraction mistake in the beginning of the question that threw off the rest of the question. I think this is why it is important to pay attention to your work in the beginning of the question (and throughout the rest of it). I also think it is important to do your math when your brain is working and ready to learn, because this way you are not only less likley to make mistakes, but also are able to learn more from your work and remember how the math works.