X(x+40)=48000

Solution for X(x+40)=48000 equation:

X(X+40)=48000

We move all terms to the left:

X(X+40)-(48000)=0

We multiply parentheses

X^2+40X-48000=0

a = 1; b = 40; c = -48000;
Δ = b2-4ac
Δ = 402-4·1·(-48000)
Δ = 193600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{193600}=440$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-440}{2*1}=\frac{-480}{2}
=-240
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+440}{2*1}=\frac{400}{2}
=200
$