-3y(-1y+-1)=12

Solution for -3y(-1y+-1)=12 equation:

-3y(-1y+-1)=12

We move all terms to the left:

-3y(-1y+-1)-(12)=0

We add all the numbers together, and all the variables

-3y(-1y-1)-12=0

We multiply parentheses

3y^2+3y-12=0

a = 3; b = 3; c = -12;
Δ = b2-4ac
Δ = 32-4·3·(-12)
Δ = 153
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{153}=\sqrt{9*17}=\sqrt{9}*\sqrt{17}=3\sqrt{17}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-3\sqrt{17}}{2*3}=\frac{-3-3\sqrt{17}}{6}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+3\sqrt{17}}{2*3}=\frac{-3+3\sqrt{17}}{6}
$