x^2-x-18=9x+6

Solution for x^2-x-18=9x+6 equation:

x^2-x-18=9x+6

We move all terms to the left:

x^2-x-18-(9x+6)=0

We add all the numbers together, and all the variables

x^2-1x-(9x+6)-18=0

We get rid of parentheses

x^2-1x-9x-6-18=0

We add all the numbers together, and all the variables

x^2-10x-24=0

a = 1; b = -10; c = -24;
Δ = b2-4ac
Δ = -102-4·1·(-24)
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-14}{2*1}=\frac{-4}{2}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+14}{2*1}=\frac{24}{2}
=12
$