How do you solve $x^2+5x-84=0$ ?

Question

16082 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-08-02T06:20:28

The solutions for the expression are:
$color(blue)(x=7, color(blue)(x=-12$

$x^2+5x–84$

We can first factorise the above expression and then proceed towards finding the solution.

Factorising by splitting the middle term

$x^2+color(blue)(5x)–84 = x^2+color(blue)(12x -7x)–84$

$=x(x+12) - 7(x +12)$

$color(blue)((x-7)(x+12)$ is the factorised form for the expression.

Now we can equate each factor with zero and obtain the solutions.

$x-7=0, color(blue)(x=7$
$x+12=0, color(blue)(x=-12$

How do you solve x^2+5x-84=0x^2+5x-84=0?