1. ## Solving an equation

Hi, i'm not sure if this in the right section so apologies if its not.

2. Originally Posted by oli212
Hi, i'm not sure if this in the right section so apologies if its not.

I need to solve the X value for the following equation:

4500 = -5X² + 390X – 30.

$4500 = -5x^2 + 390x - 30$

Move everything to one side (aka, set to zero!)

$5x^2 - 390x + 4470 = 0$

Simplify this by dividing by five.

$x^2 - 78x + 894 = 0$

$x = \frac{78 \pm \sqrt{78^2 - 4(894)(1)}}{2}$
$x = \frac{78 \pm \sqrt{6084 - 3576}}{2}$
$x = \frac{78 \pm \sqrt{2508}}{2}$
$x = 39 \pm \sqrt{627}$