4.9*x^2+2.46*x-20=0

Solution for 4.9*x^2+2.46*x-20=0 equation:

4.9x^2+2.46x-20=0

a = 4.9; b = 2.46; c = -20;
Δ = b2-4ac
Δ = 2.462-4·4.9·(-20)
Δ = 398.0516
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{-(2.46)-\sqrt{398.0516}}{2*4.9}=\frac{-2.46-\sqrt{398.0516}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.46)+\sqrt{398.0516}}{2*4.9}=\frac{-2.46+\sqrt{398.0516}}{9.8}
$