(x-6)(x+9)=756

Solution for (x-6)(x+9)=756 equation:

(x-6)(x+9)=756

We move all terms to the left:

(x-6)(x+9)-(756)=0

We multiply parentheses ..

(+x^2+9x-6x-54)-756=0

We get rid of parentheses

x^2+9x-6x-54-756=0

We add all the numbers together, and all the variables

x^2+3x-810=0

a = 1; b = 3; c = -810;
Δ = b2-4ac
Δ = 32-4·1·(-810)
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-57}{2*1}=\frac{-60}{2}
=-30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+57}{2*1}=\frac{54}{2}
=27
$