9.8x^2-20x-45=0

Solution for 9.8x^2-20x-45=0 equation:

9.8x^2-20x-45=0

a = 9.8; b = -20; c = -45;
Δ = b2-4ac
Δ = -202-4·9.8·(-45)
Δ = 2164
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2164}=\sqrt{4*541}=\sqrt{4}*\sqrt{541}=2\sqrt{541}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-2\sqrt{541}}{2*9.8}=\frac{20-2\sqrt{541}}{19.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+2\sqrt{541}}{2*9.8}=\frac{20+2\sqrt{541}}{19.6}
$