y^2+6y-87=0

Solution for y^2+6y-87=0 equation:

y^2+6y-87=0

a = 1; b = 6; c = -87;
Δ = b2-4ac
Δ = 62-4·1·(-87)
Δ = 384
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:

$\sqrt{\Delta}=\sqrt{384}=\sqrt{64*6}=\sqrt{64}*\sqrt{6}=8\sqrt{6}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-8\sqrt{6}}{2*1}=\frac{-6-8\sqrt{6}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+8\sqrt{6}}{2*1}=\frac{-6+8\sqrt{6}}{2}
$