x^2+66x-87=0

Solution for x^2+66x-87=0 equation:

x^2+66x-87=0

a = 1; b = 66; c = -87;
Δ = b2-4ac
Δ = 662-4·1·(-87)
Δ = 4704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4704}=\sqrt{784*6}=\sqrt{784}*\sqrt{6}=28\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(66)-28\sqrt{6}}{2*1}=\frac{-66-28\sqrt{6}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(66)+28\sqrt{6}}{2*1}=\frac{-66+28\sqrt{6}}{2}
$