Week 10 – Factoring Polynomials Review

Factoring is writing an expression as a product of factors.

Common?

Difference of squares

Pattern

Easy

Ugly

ex. Factor x² – 6x -16

Find two numbers whose product is -16 and whose sum is -6: 2 and -8.

So, (x + 2) (x – 8)

 

ex. Factor 3y(y + 2) – 9 (y + 2)

To easily factor this, replace y + 2 with a variable such as a.

Now factor 3ya – 9a  —> has common factor of 3 and a

3a(y – 3)

Substitute a = y + 2 in the expression above.

So,  3(y + 2)(y – 3)