y^2-12y-27.96=0

Solution for y^2-12y-27.96=0 equation:

y^2-12y-27.96=0

a = 1; b = -12; c = -27.96;
Δ = b2-4ac
Δ = -122-4·1·(-27.96)
Δ = 255.84
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-\sqrt{255.84}}{2*1}=\frac{12-\sqrt{255.84}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+\sqrt{255.84}}{2*1}=\frac{12+\sqrt{255.84}}{2}
$