25x^2+4x-256=0

Solution for 25x^2+4x-256=0 equation:

25x^2+4x-256=0

a = 25; b = 4; c = -256;
Δ = b2-4ac
Δ = 42-4·25·(-256)
Δ = 25616
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:

$\sqrt{\Delta}=\sqrt{25616}=\sqrt{16*1601}=\sqrt{16}*\sqrt{1601}=4\sqrt{1601}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{1601}}{2*25}=\frac{-4-4\sqrt{1601}}{50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{1601}}{2*25}=\frac{-4+4\sqrt{1601}}{50}
$