How do you factor $x^2-8x-20$ ?

Question

25031 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-04-10T16:57:54

$( x + 2 ) ( x - 10 )$ is the factorised form of the expression.

$x^2 - 8x - 20$

We can Split the Middle Term of this expression to factorise it.

In this technique, if we have to factorise an expression like $ax^2 + bx + c$ , we need to think of 2 numbers such that:

$N_1*N_2 = a*c = 1*-20 =- 20$

AND

$N_1 +N_2 = b = -8$

After trying out a few numbers we get $N_1 = 2$ and $N_2 =-10$
$2 * (-10) = -20$ , and $2+(-10)= - 8$

$x^2 - 8x - 20 = x^2 - 10x + 2x - 20$

$=x ( x - 10 ) + 2 ( x - 1 0)$

$( x + 2 ) ( x - 10 )$ is the factorised form of the expression.

How do you factor x^2-8x-20x^2-8x-20?