Week 14 – Math 11

This week in math 11 we learned how to multiply and divide rational expressions. The most important thing to remember when doing this is to always factor out the expressions, this is important so that you can cancel out some parts to make the expression smaller and easier to work with. You also need to remember that when a question asks you to multiply you flip the fraction on the other side of the divide sign (not all of them if there are more) then multiply.

For example if your expression is the first thing you will do is look to see if any of the numbers can be reduced (a top and bottom number or variable anywhere can both be divided by the same number). For this equation the 10 and 5 can both be divided by 5, the two m’s can cancel each other out and the and p can both be divided by p. This leaves you with .

For ones that are dividing this is how they work. If the expression looks like the first thing you are going to want to do is flip the second fraction so 10b is on the top and 4 is on the bottom. From here you will do the same thing and look to see if there is anything two number can be divided by to simplify the fraction down then you will find your answer. For this answer it would be , since it is over 1 you don’t have to write it because it is the same as .

As you keep going with this some of the questions will then have two variables which can get very confusing but as long as you remember to factor out the fractions and remember to invert the fraction beside a divide sign then multiply, you just need to be cautious when cancelling out factors and watch signs because that is where a lot of mistakes happen.