x*x+18x-63=0

Solution for x*x+18x-63=0 equation:

x*x+18x-63=0

We add all the numbers together, and all the variables

18x+x*x-63=0

Wy multiply elements

x^2+18x-63=0

a = 1; b = 18; c = -63;
Δ = b2-4ac
Δ = 182-4·1·(-63)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-24}{2*1}=\frac{-42}{2}
=-21
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+24}{2*1}=\frac{6}{2}
=3
$