15x-2x^2=25

Solution for 15x-2x^2=25 equation:

15x-2x^2=25

We move all terms to the left:

15x-2x^2-(25)=0

a = -2; b = 15; c = -25;
Δ = b2-4ac
Δ = 152-4·(-2)·(-25)
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-5}{2*-2}=\frac{-20}{-4}
=+5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+5}{2*-2}=\frac{-10}{-4}
=2+1/2
$