40-4.9x^2=0

Solution for 40-4.9x^2=0 equation:

40-4.9x^2=0

a = -4.9; b = 0; c = +40;
Δ = b2-4ac
Δ = 02-4·(-4.9)·40
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-28}{2*-4.9}=\frac{-28}{-9.8}
=2+6/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+28}{2*-4.9}=\frac{28}{-9.8}
=-2+6/7
$