x2=-18x=72

Solution for x2=-18x=72 equation:

x2=-18x=72

We move all terms to the left:

x2-(-18x)=0

We add all the numbers together, and all the variables

x^2-(-18x)=0

We get rid of parentheses

x^2+18x=0

a = 1; b = 18; c = 0;
Δ = b2-4ac
Δ = 182-4·1·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-18}{2*1}=\frac{-36}{2}
=-18
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+18}{2*1}=\frac{0}{2}
=0
$