5x^2+20x-70=0

Solution for 5x^2+20x-70=0 equation:

5x^2+20x-70=0

a = 5; b = 20; c = -70;
Δ = b2-4ac
Δ = 202-4·5·(-70)
Δ = 1800
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:

$\sqrt{\Delta}=\sqrt{1800}=\sqrt{900*2}=\sqrt{900}*\sqrt{2}=30\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-30\sqrt{2}}{2*5}=\frac{-20-30\sqrt{2}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+30\sqrt{2}}{2*5}=\frac{-20+30\sqrt{2}}{10}
$