Write each rational expression in simplest form and list the values of the variables for which the fraction is undefined.

1. x^2-7x+12/x^2+2x-15

2. 5y^2-20/y^2+4y+4

3. -7+7a/21a^2-21

4. 5(1-b)+15/b^2-16

1 answer

#2:
5(y^2-4)/(y+2)^2

5(y+2)(y-2)/(y+2)^2

5(y-2)/(y+2)
undefined where y+2=0, or y = -2.

Do the others in like wise. What do you get?