How do you multiply and simplify \frac { 1} { x + 2} \cdot \frac { x ^ { 2} - 9x + 20} { 4- x }?

1 Answer
Mar 18, 2017

(5-x)/(x+2)

Explanation:

You would factor x^2-9x+20=(x-5)(x-4) and substitute it in the expression to get:

1/(x+2)*((x-5)(x-4))/(4-x)

Since (x-4)/(4-x)=-1, you get:

1/(x+2)*((x-5)cancel((x-4))^-1)/cancel((4-x))

=(5-x)/(x+2)