(2x-22)(x+2)=28

Solution for (2x-22)(x+2)=28 equation:

(2x-22)(x+2)=28

We move all terms to the left:

(2x-22)(x+2)-(28)=0

We multiply parentheses ..

(+2x^2+4x-22x-44)-28=0

We get rid of parentheses

2x^2+4x-22x-44-28=0

We add all the numbers together, and all the variables

2x^2-18x-72=0

a = 2; b = -18; c = -72;
Δ = b2-4ac
Δ = -182-4·2·(-72)
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-30}{2*2}=\frac{-12}{4}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+30}{2*2}=\frac{48}{4}
=12
$