-4y+4y^2-60=0

Solution for -4y+4y^2-60=0 equation:

-4y+4y^2-60=0

a = 4; b = -4; c = -60;
Δ = b2-4ac
Δ = -42-4·4·(-60)
Δ = 976
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:

$\sqrt{\Delta}=\sqrt{976}=\sqrt{16*61}=\sqrt{16}*\sqrt{61}=4\sqrt{61}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-4\sqrt{61}}{2*4}=\frac{4-4\sqrt{61}}{8}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+4\sqrt{61}}{2*4}=\frac{4+4\sqrt{61}}{8}
$