X(x+10)=2000

Solution for X(x+10)=2000 equation:

X(X+10)=2000

We move all terms to the left:

X(X+10)-(2000)=0

We multiply parentheses

X^2+10X-2000=0

a = 1; b = 10; c = -2000;
Δ = b2-4ac
Δ = 102-4·1·(-2000)
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-90}{2*1}=\frac{-100}{2}
=-50
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+90}{2*1}=\frac{80}{2}
=40
$