y^2+4y-27=0

Solution for y^2+4y-27=0 equation:

y^2+4y-27=0

a = 1; b = 4; c = -27;
Δ = b2-4ac
Δ = 42-4·1·(-27)
Δ = 124
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:

$\sqrt{\Delta}=\sqrt{124}=\sqrt{4*31}=\sqrt{4}*\sqrt{31}=2\sqrt{31}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-2\sqrt{31}}{2*1}=\frac{-4-2\sqrt{31}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+2\sqrt{31}}{2*1}=\frac{-4+2\sqrt{31}}{2}
$