x2-40x-2100=0

Solution for x2-40x-2100=0 equation:

x2-40x-2100=0

We add all the numbers together, and all the variables

x^2-40x-2100=0

a = 1; b = -40; c = -2100;
Δ = b2-4ac
Δ = -402-4·1·(-2100)
Δ = 10000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10000}=100$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-100}{2*1}=\frac{-60}{2}
=-30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+100}{2*1}=\frac{140}{2}
=70
$