X2+12x=640

Solution for X2+12x=640 equation:

X2+12X=640

We move all terms to the left:

X2+12X-(640)=0

We add all the numbers together, and all the variables

X^2+12X-640=0

a = 1; b = 12; c = -640;
Δ = b2-4ac
Δ = 122-4·1·(-640)
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-52}{2*1}=\frac{-64}{2}
=-32
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+52}{2*1}=\frac{40}{2}
=20
$