5*x^2+60x-91=0

Solution for 5*x^2+60x-91=0 equation:

5x^2+60x-91=0

a = 5; b = 60; c = -91;
Δ = b2-4ac
Δ = 602-4·5·(-91)
Δ = 5420
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:

$\sqrt{\Delta}=\sqrt{5420}=\sqrt{4*1355}=\sqrt{4}*\sqrt{1355}=2\sqrt{1355}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-2\sqrt{1355}}{2*5}=\frac{-60-2\sqrt{1355}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+2\sqrt{1355}}{2*5}=\frac{-60+2\sqrt{1355}}{10}
$