2x(6x+4)=15

Solution for 2x(6x+4)=15 equation:

2x(6x+4)=15

We move all terms to the left:

2x(6x+4)-(15)=0

We multiply parentheses

12x^2+8x-15=0

a = 12; b = 8; c = -15;
Δ = b2-4ac
Δ = 82-4·12·(-15)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-28}{2*12}=\frac{-36}{24}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+28}{2*12}=\frac{20}{24}
=5/6
$