2x^2+3x+15+3x^2+x-20=180

Solution for 2x^2+3x+15+3x^2+x-20=180 equation:

2x^2+3x+15+3x^2+x-20=180

We move all terms to the left:

2x^2+3x+15+3x^2+x-20-(180)=0

We add all the numbers together, and all the variables

5x^2+4x-185=0

a = 5; b = 4; c = -185;
Δ = b2-4ac
Δ = 42-4·5·(-185)
Δ = 3716
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:

$\sqrt{\Delta}=\sqrt{3716}=\sqrt{4*929}=\sqrt{4}*\sqrt{929}=2\sqrt{929}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-2\sqrt{929}}{2*5}=\frac{-4-2\sqrt{929}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+2\sqrt{929}}{2*5}=\frac{-4+2\sqrt{929}}{10}
$