-25x^2+50x+70=0

Solution for -25x^2+50x+70=0 equation:

-25x^2+50x+70=0

a = -25; b = 50; c = +70;
Δ = b2-4ac
Δ = 502-4·(-25)·70
Δ = 9500
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:

$\sqrt{\Delta}=\sqrt{9500}=\sqrt{100*95}=\sqrt{100}*\sqrt{95}=10\sqrt{95}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-10\sqrt{95}}{2*-25}=\frac{-50-10\sqrt{95}}{-50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+10\sqrt{95}}{2*-25}=\frac{-50+10\sqrt{95}}{-50}
$