(x-3)(x+2)=90

Solution for (x-3)(x+2)=90 equation:

(x-3)(x+2)=90

We move all terms to the left:

(x-3)(x+2)-(90)=0

We multiply parentheses ..

(+x^2+2x-3x-6)-90=0

We get rid of parentheses

x^2+2x-3x-6-90=0

We add all the numbers together, and all the variables

x^2-1x-96=0

a = 1; b = -1; c = -96;
Δ = b2-4ac
Δ = -12-4·1·(-96)
Δ = 385
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-\sqrt{385}}{2*1}=\frac{1-\sqrt{385}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{385}}{2*1}=\frac{1+\sqrt{385}}{2}
$