3x(5x+2)=180

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

3x(5x+2)=180

We move all terms to the left:

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

We multiply parentheses

15x^2+6x-180=0

a = 15; b = 6; c = -180;
Δ = b2-4ac
Δ = 62-4·15·(-180)
Δ = 10836
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:

$\sqrt{\Delta}=\sqrt{10836}=\sqrt{36*301}=\sqrt{36}*\sqrt{301}=6\sqrt{301}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6\sqrt{301}}{2*15}=\frac{-6-6\sqrt{301}}{30}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6\sqrt{301}}{2*15}=\frac{-6+6\sqrt{301}}{30}
$