(4x)(9x-1)=180

Solution for (4x)(9x-1)=180 equation:

(4x)(9x-1)=180

We move all terms to the left:

(4x)(9x-1)-(180)=0

We multiply parentheses

36x^2-4x-180=0

a = 36; b = -4; c = -180;
Δ = b2-4ac
Δ = -42-4·36·(-180)
Δ = 25936
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:

$\sqrt{\Delta}=\sqrt{25936}=\sqrt{16*1621}=\sqrt{16}*\sqrt{1621}=4\sqrt{1621}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-4\sqrt{1621}}{2*36}=\frac{4-4\sqrt{1621}}{72}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+4\sqrt{1621}}{2*36}=\frac{4+4\sqrt{1621}}{72}
$