-0.025x^2+4.5x+9=0

Solution for -0.025x^2+4.5x+9=0 equation:

-0.025x^2+4.5x+9=0

a = -0.025; b = 4.5; c = +9;
Δ = b2-4ac
Δ = 4.52-4·(-0.025)·9
Δ = 21.15
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{-(4.5)-\sqrt{21.15}}{2*-0.025}=\frac{-4.5-\sqrt{21.15}}{-0.05}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4.5)+\sqrt{21.15}}{2*-0.025}=\frac{-4.5+\sqrt{21.15}}{-0.05}
$