y^2-14y-30=-18

Solution for y^2-14y-30=-18 equation:

y^2-14y-30=-18

We move all terms to the left:

y^2-14y-30-(-18)=0

We add all the numbers together, and all the variables

y^2-14y-12=0

a = 1; b = -14; c = -12;
Δ = b2-4ac
Δ = -142-4·1·(-12)
Δ = 244
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:

$\sqrt{\Delta}=\sqrt{244}=\sqrt{4*61}=\sqrt{4}*\sqrt{61}=2\sqrt{61}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-2\sqrt{61}}{2*1}=\frac{14-2\sqrt{61}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+2\sqrt{61}}{2*1}=\frac{14+2\sqrt{61}}{2}
$