25x^2-40x-11=0

Solution for 25x^2-40x-11=0 equation:

25x^2-40x-11=0

a = 25; b = -40; c = -11;
Δ = b2-4ac
Δ = -402-4·25·(-11)
Δ = 2700
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:

$\sqrt{\Delta}=\sqrt{2700}=\sqrt{900*3}=\sqrt{900}*\sqrt{3}=30\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-30\sqrt{3}}{2*25}=\frac{40-30\sqrt{3}}{50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+30\sqrt{3}}{2*25}=\frac{40+30\sqrt{3}}{50}
$