9x(10x+4)=180

Solution for 9x(10x+4)=180 equation:

9x(10x+4)=180

We move all terms to the left:

9x(10x+4)-(180)=0

We multiply parentheses

90x^2+36x-180=0

a = 90; b = 36; c = -180;
Δ = b2-4ac
Δ = 362-4·90·(-180)
Δ = 66096
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:

$\sqrt{\Delta}=\sqrt{66096}=\sqrt{1296*51}=\sqrt{1296}*\sqrt{51}=36\sqrt{51}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(36)-36\sqrt{51}}{2*90}=\frac{-36-36\sqrt{51}}{180}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(36)+36\sqrt{51}}{2*90}=\frac{-36+36\sqrt{51}}{180}
$