3x(2x-5)=180

Solution for 3x(2x-5)=180 equation:

3x(2x-5)=180

We move all terms to the left:

3x(2x-5)-(180)=0

We multiply parentheses

6x^2-15x-180=0

a = 6; b = -15; c = -180;
Δ = b2-4ac
Δ = -152-4·6·(-180)
Δ = 4545
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:

$\sqrt{\Delta}=\sqrt{4545}=\sqrt{9*505}=\sqrt{9}*\sqrt{505}=3\sqrt{505}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-3\sqrt{505}}{2*6}=\frac{15-3\sqrt{505}}{12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+3\sqrt{505}}{2*6}=\frac{15+3\sqrt{505}}{12}
$