-5x(x-30)=-25

Solution for -5x(x-30)=-25 equation:

-5x(x-30)=-25

We move all terms to the left:

-5x(x-30)-(-25)=0

We add all the numbers together, and all the variables

-5x(x-30)+25=0

We multiply parentheses

-5x^2+150x+25=0

a = -5; b = 150; c = +25;
Δ = b2-4ac
Δ = 1502-4·(-5)·25
Δ = 23000
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:

$\sqrt{\Delta}=\sqrt{23000}=\sqrt{100*230}=\sqrt{100}*\sqrt{230}=10\sqrt{230}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(150)-10\sqrt{230}}{2*-5}=\frac{-150-10\sqrt{230}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(150)+10\sqrt{230}}{2*-5}=\frac{-150+10\sqrt{230}}{-10}
$