25x^2-30x-4=0

Solution for 25x^2-30x-4=0 equation:

25x^2-30x-4=0

a = 25; b = -30; c = -4;
Δ = b2-4ac
Δ = -302-4·25·(-4)
Δ = 1300
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:

$\sqrt{\Delta}=\sqrt{1300}=\sqrt{100*13}=\sqrt{100}*\sqrt{13}=10\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-10\sqrt{13}}{2*25}=\frac{30-10\sqrt{13}}{50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+10\sqrt{13}}{2*25}=\frac{30+10\sqrt{13}}{50}
$