(x+8)(x-3)=30

Solution for (x+8)(x-3)=30 equation:

(x+8)(x-3)=30

We move all terms to the left:

(x+8)(x-3)-(30)=0

We multiply parentheses ..

(+x^2-3x+8x-24)-30=0

We get rid of parentheses

x^2-3x+8x-24-30=0

We add all the numbers together, and all the variables

x^2+5x-54=0

a = 1; b = 5; c = -54;
Δ = b2-4ac
Δ = 52-4·1·(-54)
Δ = 241
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{-(5)-\sqrt{241}}{2*1}=\frac{-5-\sqrt{241}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{241}}{2*1}=\frac{-5+\sqrt{241}}{2}
$