(x+90)7x=360

Solution for (x+90)7x=360 equation:

(x+90)7x=360

We move all terms to the left:

(x+90)7x-(360)=0

We multiply parentheses

7x^2+630x-360=0

a = 7; b = 630; c = -360;
Δ = b2-4ac
Δ = 6302-4·7·(-360)
Δ = 406980
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:

$\sqrt{\Delta}=\sqrt{406980}=\sqrt{36*11305}=\sqrt{36}*\sqrt{11305}=6\sqrt{11305}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(630)-6\sqrt{11305}}{2*7}=\frac{-630-6\sqrt{11305}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(630)+6\sqrt{11305}}{2*7}=\frac{-630+6\sqrt{11305}}{14}
$