5(x-1)*2x-15=2x+15

Solution for 5(x-1)*2x-15=2x+15 equation:

5(x-1)*2x-15=2x+15

We move all terms to the left:

5(x-1)*2x-15-(2x+15)=0

We multiply parentheses

10x^2-10x-(2x+15)-15=0

We get rid of parentheses

10x^2-10x-2x-15-15=0

We add all the numbers together, and all the variables

10x^2-12x-30=0

a = 10; b = -12; c = -30;
Δ = b2-4ac
Δ = -122-4·10·(-30)
Δ = 1344
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:

$\sqrt{\Delta}=\sqrt{1344}=\sqrt{64*21}=\sqrt{64}*\sqrt{21}=8\sqrt{21}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-8\sqrt{21}}{2*10}=\frac{12-8\sqrt{21}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+8\sqrt{21}}{2*10}=\frac{12+8\sqrt{21}}{20}
$