(3x)(4x-1)+90=180

Solution for (3x)(4x-1)+90=180 equation:

(3x)(4x-1)+90=180

We move all terms to the left:

(3x)(4x-1)+90-(180)=0

We add all the numbers together, and all the variables

3x(4x-1)-90=0

We multiply parentheses

12x^2-3x-90=0

a = 12; b = -3; c = -90;
Δ = b2-4ac
Δ = -32-4·12·(-90)
Δ = 4329
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:

$\sqrt{\Delta}=\sqrt{4329}=\sqrt{9*481}=\sqrt{9}*\sqrt{481}=3\sqrt{481}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-3\sqrt{481}}{2*12}=\frac{3-3\sqrt{481}}{24}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+3\sqrt{481}}{2*12}=\frac{3+3\sqrt{481}}{24}
$