-.75x(12x+60)=-x-8x-15

Solution for -.75x(12x+60)=-x-8x-15 equation:

-.75x(12x+60)=-x-8x-15

We move all terms to the left:

-.75x(12x+60)-(-x-8x-15)=0

We add all the numbers together, and all the variables

-.75x(12x+60)-(-9x-15)=0

We multiply parentheses

-12x^2-60x-(-9x-15)=0

We get rid of parentheses

-12x^2-60x+9x+15=0

We add all the numbers together, and all the variables

-12x^2-51x+15=0

a = -12; b = -51; c = +15;
Δ = b2-4ac
Δ = -512-4·(-12)·15
Δ = 3321
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:

$\sqrt{\Delta}=\sqrt{3321}=\sqrt{81*41}=\sqrt{81}*\sqrt{41}=9\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-51)-9\sqrt{41}}{2*-12}=\frac{51-9\sqrt{41}}{-24}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-51)+9\sqrt{41}}{2*-12}=\frac{51+9\sqrt{41}}{-24}
$