Question

How do I solve x² + 2x − 8 = 0?
explain please/step by step

Answer 1

-2 , 4

Explanation:

Their are 4 ways you can solve this but I am going to factorise to solve

x² + 2x − 8 = 0

Factors = 4 , -2

Sum = 2

Product = -8

x ( x + 4 ) - 2 ( x + 4 ) = 0

( x - 2 ) ( x + 4 ) = 0

x = - 2 , 4

Answer 2

It's x = -4 , 2.

Explanation:

x^2 + 2x - 8 = 0

The left side will factor to the form (x + a)(x + b).

We need 2 numbers (a and b) whose product = -8 and whose sum = +2.

These are a = 4 and b = -2, so the factors are

(x + 4)(x - 2) = 0

Now either x + 4 = 0 or x - 2 = 0,

giving x = -4, x = 2 (answer).