.85x(75+X)=125

Solution for .85x(75+X)=125 equation:

.85x(75+x)=125

We move all terms to the left:

.85x(75+x)-(125)=0

We add all the numbers together, and all the variables

.85x(x+75)-125=0

We multiply parentheses

x^2+75x-125=0

a = 1; b = 75; c = -125;
Δ = b2-4ac
Δ = 752-4·1·(-125)
Δ = 6125
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:

$\sqrt{\Delta}=\sqrt{6125}=\sqrt{1225*5}=\sqrt{1225}*\sqrt{5}=35\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(75)-35\sqrt{5}}{2*1}=\frac{-75-35\sqrt{5}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(75)+35\sqrt{5}}{2*1}=\frac{-75+35\sqrt{5}}{2}
$