X(x-15)=-50

Solution for X(x-15)=-50 equation:

X(X-15)=-50

We move all terms to the left:

X(X-15)-(-50)=0

We add all the numbers together, and all the variables

X(X-15)+50=0

We multiply parentheses

X^2-15X+50=0

a = 1; b = -15; c = +50;
Δ = b2-4ac
Δ = -152-4·1·50
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-5}{2*1}=\frac{10}{2}
=5
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+5}{2*1}=\frac{20}{2}
=10
$