3x(7x+10)=180

Solution for 3x(7x+10)=180 equation:

3x(7x+10)=180

We move all terms to the left:

3x(7x+10)-(180)=0

We multiply parentheses

21x^2+30x-180=0

a = 21; b = 30; c = -180;
Δ = b2-4ac
Δ = 302-4·21·(-180)
Δ = 16020
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:

$\sqrt{\Delta}=\sqrt{16020}=\sqrt{36*445}=\sqrt{36}*\sqrt{445}=6\sqrt{445}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-6\sqrt{445}}{2*21}=\frac{-30-6\sqrt{445}}{42}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+6\sqrt{445}}{2*21}=\frac{-30+6\sqrt{445}}{42}
$