# Thread: how to factor these algebraic fractions?

1. ## how to factor these algebraic fractions?

For #2 my book says the answer is -1. why and how??

1.) 5x + 5y
5x - 5y

2.) 5x - 5y
5y - 5x

2. Originally Posted by benjixbunn
For #2 my book says the answer is -1. why and how??
2.) 5x - 5y
5y - 5x
Because $(y-x)=-(x-y)$.

3. Originally Posted by benjixbunn
For #2 my book says the answer is -1. why and how??

1.) 5x + 5y
5x - 5y

2.) 5x - 5y
5y - 5x

$\displaystyle{\frac{5x-5y}{5y-5x}=\frac{-5(y-x)}{5(y-x)}=-1$

Tonio