x^2+70x-17=0

Solution for x^2+70x-17=0 equation:

x^2+70x-17=0

a = 1; b = 70; c = -17;
Δ = b2-4ac
Δ = 702-4·1·(-17)
Δ = 4968
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:

$\sqrt{\Delta}=\sqrt{4968}=\sqrt{36*138}=\sqrt{36}*\sqrt{138}=6\sqrt{138}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(70)-6\sqrt{138}}{2*1}=\frac{-70-6\sqrt{138}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(70)+6\sqrt{138}}{2*1}=\frac{-70+6\sqrt{138}}{2}
$