-4.9x^2+16.7x+30=0

Solution for -4.9x^2+16.7x+30=0 equation:

-4.9x^2+16.7x+30=0

a = -4.9; b = 16.7; c = +30;
Δ = b2-4ac
Δ = 16.72-4·(-4.9)·30
Δ = 866.89
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{-(16.7)-\sqrt{866.89}}{2*-4.9}=\frac{-16.7-\sqrt{866.89}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16.7)+\sqrt{866.89}}{2*-4.9}=\frac{-16.7+\sqrt{866.89}}{-9.8}
$