x2+200x=166400

Solution for x2+200x=166400 equation:

x2+200x=166400

We move all terms to the left:

x2+200x-(166400)=0

We add all the numbers together, and all the variables

x^2+200x-166400=0

a = 1; b = 200; c = -166400;
Δ = b2-4ac
Δ = 2002-4·1·(-166400)
Δ = 705600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{705600}=840$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(200)-840}{2*1}=\frac{-1040}{2}
=-520
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(200)+840}{2*1}=\frac{640}{2}
=320
$