2x(x-7)=36

Solution for 2x(x-7)=36 equation:

2x(x-7)=36

We move all terms to the left:

2x(x-7)-(36)=0

We multiply parentheses

2x^2-14x-36=0

a = 2; b = -14; c = -36;
Δ = b2-4ac
Δ = -142-4·2·(-36)
Δ = 484
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{484}=22$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-22}{2*2}=\frac{-8}{4}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+22}{2*2}=\frac{36}{4}
=9
$