X^2-40x+20x-800=2700

Solution for X^2-40x+20x-800=2700 equation:

X^2-40X+20X-800=2700

We move all terms to the left:

X^2-40X+20X-800-(2700)=0

We add all the numbers together, and all the variables

X^2-20X-3500=0

a = 1; b = -20; c = -3500;
Δ = b2-4ac
Δ = -202-4·1·(-3500)
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-120}{2*1}=\frac{-100}{2}
=-50
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+120}{2*1}=\frac{140}{2}
=70
$