-4.9x^2+8.5x=0

Solution for -4.9x^2+8.5x=0 equation:

-4.9x^2+8.5x=0

a = -4.9; b = 8.5; c = 0;
Δ = b2-4ac
Δ = 8.52-4·(-4.9)·0
Δ = 72.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8.5)-\sqrt{72.25}}{2*-4.9}=\frac{-8.5-\sqrt{72.25}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8.5)+\sqrt{72.25}}{2*-4.9}=\frac{-8.5+\sqrt{72.25}}{-9.8}
$