-25x^2+10x+11=0

Solution for -25x^2+10x+11=0 equation:

-25x^2+10x+11=0

a = -25; b = 10; c = +11;
Δ = b2-4ac
Δ = 102-4·(-25)·11
Δ = 1200
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:

$\sqrt{\Delta}=\sqrt{1200}=\sqrt{400*3}=\sqrt{400}*\sqrt{3}=20\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-20\sqrt{3}}{2*-25}=\frac{-10-20\sqrt{3}}{-50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+20\sqrt{3}}{2*-25}=\frac{-10+20\sqrt{3}}{-50}
$