X(x+15)=2250

Solution for X(x+15)=2250 equation:

X(X+15)=2250

We move all terms to the left:

X(X+15)-(2250)=0

We multiply parentheses

X^2+15X-2250=0

a = 1; b = 15; c = -2250;
Δ = b2-4ac
Δ = 152-4·1·(-2250)
Δ = 9225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{9225}=\sqrt{225*41}=\sqrt{225}*\sqrt{41}=15\sqrt{41}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15\sqrt{41}}{2*1}=\frac{-15-15\sqrt{41}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15\sqrt{41}}{2*1}=\frac{-15+15\sqrt{41}}{2}
$