-0.9x^2+45x=0

Solution for -0.9x^2+45x=0 equation:

-0.9x^2+45x=0

a = -0.9; b = 45; c = 0;
Δ = b2-4ac
Δ = 452-4·(-0.9)·0
Δ = 2025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2025}=45$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-45}{2*-0.9}=\frac{-90}{-1.8}
=+50
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+45}{2*-0.9}=\frac{0}{-1.8}
=0
$