-2.5x^2+23.75x-47.5=0

Solution for -2.5x^2+23.75x-47.5=0 equation:

-2.5x^2+23.75x-47.5=0

a = -2.5; b = 23.75; c = -47.5;
Δ = b2-4ac
Δ = 23.752-4·(-2.5)·(-47.5)
Δ = 89.0625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(23.75)-\sqrt{89.0625}}{2*-2.5}=\frac{-23.75-\sqrt{89.0625}}{-5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(23.75)+\sqrt{89.0625}}{2*-2.5}=\frac{-23.75+\sqrt{89.0625}}{-5}
$