4.905x^2-20x-25=0

Solution for 4.905x^2-20x-25=0 equation:

4.905x^2-20x-25=0

a = 4.905; b = -20; c = -25;
Δ = b2-4ac
Δ = -202-4·4.905·(-25)
Δ = 890.5
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{-(-20)-\sqrt{890.5}}{2*4.905}=\frac{20-\sqrt{890.5}}{9.81}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+\sqrt{890.5}}{2*4.905}=\frac{20+\sqrt{890.5}}{9.81}
$