(10x-5)(3x+3)=180

Solution for (10x-5)(3x+3)=180 equation:

(10x-5)(3x+3)=180

We move all terms to the left:

(10x-5)(3x+3)-(180)=0

We multiply parentheses ..

(+30x^2+30x-15x-15)-180=0

We get rid of parentheses

30x^2+30x-15x-15-180=0

We add all the numbers together, and all the variables

30x^2+15x-195=0

a = 30; b = 15; c = -195;
Δ = b2-4ac
Δ = 152-4·30·(-195)
Δ = 23625
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:

$\sqrt{\Delta}=\sqrt{23625}=\sqrt{225*105}=\sqrt{225}*\sqrt{105}=15\sqrt{105}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15\sqrt{105}}{2*30}=\frac{-15-15\sqrt{105}}{60}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15\sqrt{105}}{2*30}=\frac{-15+15\sqrt{105}}{60}
$