X(2x+x)=624

Solution for X(2x+x)=624 equation:

X(2X+X)=624

We move all terms to the left:

X(2X+X)-(624)=0

We add all the numbers together, and all the variables

X(+3X)-624=0

We multiply parentheses

3X^2-624=0

a = 3; b = 0; c = -624;
Δ = b2-4ac
Δ = 02-4·3·(-624)
Δ = 7488
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7488}=\sqrt{576*13}=\sqrt{576}*\sqrt{13}=24\sqrt{13}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{13}}{2*3}=\frac{0-24\sqrt{13}}{6}
=-\frac{24\sqrt{13}}{6}
=-4\sqrt{13}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{13}}{2*3}=\frac{0+24\sqrt{13}}{6}
=\frac{24\sqrt{13}}{6}
=4\sqrt{13}
$