Question

Solve x^2 + 2x - 8 = 0

Answer 1

Answer: x ∈ {2; -4}

Step-by-step explanation: This is a quadratic equation whose leading coefficient is 1. To factorize this equation, we can look for numbers whose product is -8 and whose sum is 2. Those numbers are 4 and -2. Then we start solving:

`(x+4)(x-2)=0\\ x+4=0 or x-2=0\\ x=-4 or x=2`