5x2+25x=90

Solution for 5x2+25x=90 equation:

5x^2+25x=90

We move all terms to the left:

5x^2+25x-(90)=0

a = 5; b = 25; c = -90;
Δ = b2-4ac
Δ = 252-4·5·(-90)
Δ = 2425
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:

$\sqrt{\Delta}=\sqrt{2425}=\sqrt{25*97}=\sqrt{25}*\sqrt{97}=5\sqrt{97}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-5\sqrt{97}}{2*5}=\frac{-25-5\sqrt{97}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+5\sqrt{97}}{2*5}=\frac{-25+5\sqrt{97}}{10}
$