-4.9x^2+9.8x+75=0

Solution for -4.9x^2+9.8x+75=0 equation:

-4.9x^2+9.8x+75=0

a = -4.9; b = 9.8; c = +75;
Δ = b2-4ac
Δ = 9.82-4·(-4.9)·75
Δ = 1566.04
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{-(9.8)-\sqrt{1566.04}}{2*-4.9}=\frac{-9.8-\sqrt{1566.04}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9.8)+\sqrt{1566.04}}{2*-4.9}=\frac{-9.8+\sqrt{1566.04}}{-9.8}
$