# Factoring polynomials: $x^2 + bx + c$

### Factoring polynomials: $x^2 + bx + c$

This form of polynomials can be often factorized into a product of two binomials. Sometimes, we need to find the common factor of the polynomial before factorizing. We will learn it all in this lesson.

#### Lessons

• Introduction
a)

"What is the cross-multiplying method of factoring? (a.k.a the Decomposition method)

• - How does it work?
• - How to use it?

• 1.
Factor the following
a)
${x^2 +7x +10}$

b)
${x^2-4x+4}$

c)
${x^2+7x-30}$

d)
${x^2-4x-21}$

• 2.
Factor with common factoring first
a)
${4x^2+20x+24}$

b)
${-4x^2 - 28x + 120}$

c)
${x^2-12xy+36y^2}$

d)
${-x^3y^2-3x^2y^3+4xy^4}$

e)
${1\over4}{x^3-x^2-8x}$

• 3.
Factor with unusual exponents
a)
${x^{6n}-3x^{3n}+2}$

b)
${x^{2n}-7x^nx^m+10x^{2m}}$

c)
${(x-2y)^2-8a(x-2y)+15a^2}$