2.5x^2+30x-25=0

Solution for 2.5x^2+30x-25=0 equation:

2.5x^2+30x-25=0

a = 2.5; b = 30; c = -25;
Δ = b2-4ac
Δ = 302-4·2.5·(-25)
Δ = 1150
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:

$\sqrt{\Delta}=\sqrt{1150}=\sqrt{25*46}=\sqrt{25}*\sqrt{46}=5\sqrt{46}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-5\sqrt{46}}{2*2.5}=\frac{-30-5\sqrt{46}}{5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+5\sqrt{46}}{2*2.5}=\frac{-30+5\sqrt{46}}{5}
$