x*(x-28)=150

Solution for x*(x-28)=150 equation:

x(x-28)=150

We move all terms to the left:

x(x-28)-(150)=0

We multiply parentheses

x^2-28x-150=0

a = 1; b = -28; c = -150;
Δ = b2-4ac
Δ = -282-4·1·(-150)
Δ = 1384
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:

$\sqrt{\Delta}=\sqrt{1384}=\sqrt{4*346}=\sqrt{4}*\sqrt{346}=2\sqrt{346}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-28)-2\sqrt{346}}{2*1}=\frac{28-2\sqrt{346}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-28)+2\sqrt{346}}{2*1}=\frac{28+2\sqrt{346}}{2}
$