How can finding the factor pairs of the constant in a trinomial help me factor the trinomial???

Printable View

- Oct 17th 2012, 06:29 PMford2008Factor pairs
How can finding the factor pairs of the constant in a trinomial help me factor the trinomial???

- Oct 17th 2012, 06:39 PMMarkFLRe: Factor pairs
If you are given a quadratic in the form:

$\displaystyle x^2+ax+b$

Finding the factor pair of*b*whose sum is*a*, will easily allow you to factor the quadratic.

Suppose $\displaystyle b=cd$ where $\displaystyle a=c+d$, then we may write:

$\displaystyle x^2+ax+b=(x+c)(x+d)$

For the more general quadratic:

$\displaystyle ax^2+bx+c$

we want to find the factor pair of $\displaystyle ac$ whose sum is $\displaystyle b$.