How do you solve $x²+2x-24=0$ algebraically?

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Answer 1 · 2016-03-21T19:15:44

Complete the square to find:

$x=4$ or $x=-6$

Complete the square $x^2+2x+1$ then use the difference of squares identity:

$a^2-b^2 = (a-b)(a+b)$

with $a=(x+1)$ and $b=5$ as follows:

$0 = x^2+2x-24$

$=x^2+2x+1-1-24$

$=(x+1)^2-5^2$

$=((x+1)-5)((x+1)+5)$

$=(x-4)(x+6)$

So $x=4$ or $x=-6$

How do you solve x²+2x-24=0x²+2x-24=0 algebraically?