Year: 2021

This week in Pre-Calc 11, we started our “solving quadratic equations”. We started off by reviewing and working on our factoring skills. In this blog post I am going to focus on how to factor a trinomial using the box method we have worked on throughout grade 10 and grade 11.

Essentially factoring is breaking an equation down to its prime form where the numbers now have nothing in common and can’t be broken down anymore.

Step 1: Write out your product and sum. How you get your product is multiplying the last number with the first, so in this case 5 and 3=15. And your sum is the middle number. Writing it out helps you not have to do so much mental math, which is where you will make errors.

Step 2: In this step you are going to determine what two numbers multiply to equal 15, but add to equal 16. So essentially what ever multiplies to equal your product needs to add to your sum. In this case 15×1=15, while 15+1=16.

Step 3: Now you’re going to draw your box and place the numbers in. The 1x and 15x doesn’t matter if they switch but the 5x^2 and the 3 need to be in the positions you see them in.

Step 4: Now you to determine what numbers you can put on the outside of the box that would multiply and give the product in the box. Sometimes this take trying out some numbers and then needed to change them before you’re done.

Step 5: This is your final step and it is writing out the final factored form of the equation.

And that’s all. A way to double check you did everything correct is to solve this factored equation and it should equal the equation you started with.

This week in pre-calc we finished up our roots and powers unit and started up our radical and operations unit, which is just growing off of what we did in our powers and roots unit as we are still using mixed and entire radicals and many other skills from that unit.

In this blog post I am going to explain how to add and subtract roots. I find this very similar to adding and subtract fractions, as when adding fractions you must have the same base, well in this case you must have the same radicand and just add the two coefficients.

Step 1: The first thing you’ll notice is that in this example the radicands aren’t the same. But I notice that they’re all perfect squares so I am going to pull out the perfect square and put it out front, now it is the coefficient.

Step 2: Now I notice all of my radicands are the same I am simply just going to add/subtract my coefficients. If this were a more complicated questions there could be some simplifying I have to do but in this example this is the final step.

Sometimes you have to put your radicand into a mixed radical to get the same radicand. I will show how to do that now.

In that example you can see I followed the same steps but I put them into mixed radicals. I then added the like ones and got my answer.

For adding and subtracting radicals you just have to remember to make them alike and if they can be alike then you just leave them.

This week in math we had our first unit test and started our second unit, which is radical operations and equations. In this blog post I am going to focus on how to add or subtract roots.

When adding or subtracting it is like simplifying variables- add like terms. So when you’re simplifying variables you can’t add a with b, it just doesn’t work. And that is the same thing we see here. The numbers in the square roots must all be the same to be able to add them.

I will do 2 examples. Once you see it it will be pretty easy to catch onto.

That is our example question.

Step 1: The first thing I am going to notice is that everything inside all three roots are alike, meaning we can add them together.

Step 2: This is the final step. Just add together all the coefficients and leave the base the same.

We will do a harder questions which take some simplifying to be able to gather like terms.

As you can see in this example I cant see any like terms, so what I am going to try to do is simplify it. How I am going to do that is try to see if any perfect square numbers are a factor of it or divide into it and then just simply making them into a mixed radical.

Step 1: The first thing I am going to do is see if I can break these numbers down into some perfect square numbers. I like to put them on top of the square root it makes it easier to see for me.

Step 2: In this step I am going to write my prime factors down into mixed radicals, exactly like we did last unit and now I can see I have the same base in all of them and can subtract them now.

Step 3: In this final step I am simply just subtracting all the coefficients.

And that is all you need to know. My advice would be to make sure you get your square root numbers right to make sure you do everything else right!

This week in Pre Calc 11 we looked at different things. In this weeks blog post I am going to explain how to do mixed radicals.

When doing mixed radicals I prefer to make a factor tree. It helps me be able to visualize it and easily see what my perfect square, cube and so on is going to be without having to do very much work. I find that when putting bigger numbers into a mixed radical a factor tree helps me keep my questions organized so when I look back at it later I am easily able to identify what I did.

Step 1: When you get your question the first step is to break it down into its prime factors. As you can see I broke down 108 all the way down to it’s prime factors via a factor tree.

Step 2: The second thing I do is take my prime factors and put them in a cubed root. I then circle my groups of three numbers, what I mean by that is because there is three three’s I know that is going to be a perfect cube.

Step 3: In this final step I pulled out the three. The three came from the three 3’s multiplied together but because they’re in a cubed root they’re going to equal 3 anyways. And as you can see there is a 4 inside the cubed root. Well that 4 comes from the two left over numbers, which in this case happens to be 2 and 2 so when multiplied together gives us 4.

Tip* Don’t forget if it’s a cubed root and fourth root and so on to make sure you put the little three or whatever it is on the square root.

It’s that simple! Just three simple steps. I will do one more example.

In this example you can see I followed the same steps, the only difference was that at my second step I needed to see 4 of the same numbers because it was a fourth root.

And that is all you need to know for mixed radicals. The last thing I am going to add is if at your second step, if you needed a cubed root and you didn’t have three of the same numbers that mixed radical wouldn’t work and your answer would be “not possible”. Just remember these three simple steps and you will be good!

 

This was our first week back at school after a long summer. We started off with a review on types of numbers and then we expanded to a new concept which is entire radicals and mixed radicals. For example √3 is an entire radical while 5√3 is a mixed radical. The difference is an entire radical has a coefficient that is just 1 so we don’t write it while a mixed radical has a coefficient other than 1.

In this blog post I will explain the two ways of getting a mixed fraction.

Way 1

Step 1:

So as you can see we are using square root of 32. I’m going to think what two number multiply to have a product of 32 while one being a perfect square.

Step 2:

In this step I showed separately square root of 8 multiplied by square root of 8. I find it easier to put the perfect square in front because I’m going to be pulling that one out anyway.

Step 3:

In this final step you can see I pulled out a 2 in front of square root of 8, I got that 2 because I square rooted the 4 which gives me 2 and because 8 has no square root you just leave it.

This way of doing it is fast and easy and works really well when you are working with smaller numbers. I find when you are using bigger number this next way is much easier and saves me time.

Way 2 

Step 1:

So in this example I’m starting with a bigger number. As you can see I broke it down into a number tree like we learnt how to last year, getting all the prime factors.

Step 2:

So in this step I took all the prime factors and put them into a big square root. As you can see I circled all the pairs of numbers. Those are the numbers I’m going to pull out and put out in front. So I would go 2×2 which 4 then square rooted is 2 and same thing for the 3’s, 3×3=9 square rooted is 3 and then I am going to multiply 2 and 3 which is going to give me 6.

Step 3:

This is the final step. I explained how to get the 6 but where did the 10 come from? If you look at our big square root the two numbers left over that weren’t in a pair were 2 and 5. I am going to multiply them together and that’s where the 10 comes from. And that’s it!

I find both of these methods useful, depending on how big the number is depends on what method i am going to use!