(x)(x+5)(8)=288

Solution for (x)(x+5)(8)=288 equation:

(x)(x+5)(8)=288

We move all terms to the left:

(x)(x+5)(8)-(288)=0

We multiply parentheses

8x^2+40x-288=0

a = 8; b = 40; c = -288;
Δ = b2-4ac
Δ = 402-4·8·(-288)
Δ = 10816
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10816}=104$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-104}{2*8}=\frac{-144}{16}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+104}{2*8}=\frac{64}{16}
=4
$