(x-2)(x+5)=156

Solution for (x-2)(x+5)=156 equation:

(x-2)(x+5)=156

We move all terms to the left:

(x-2)(x+5)-(156)=0

We multiply parentheses ..

(+x^2+5x-2x-10)-156=0

We get rid of parentheses

x^2+5x-2x-10-156=0

We add all the numbers together, and all the variables

x^2+3x-166=0

a = 1; b = 3; c = -166;
Δ = b2-4ac
Δ = 32-4·1·(-166)
Δ = 673
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{-(3)-\sqrt{673}}{2*1}=\frac{-3-\sqrt{673}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{673}}{2*1}=\frac{-3+\sqrt{673}}{2}
$