-4.9x^2+12.86x=-40

Solution for -4.9x^2+12.86x=-40 equation:

-4.9x^2+12.86x=-40

We move all terms to the left:

-4.9x^2+12.86x-(-40)=0

We add all the numbers together, and all the variables

-4.9x^2+12.86x+40=0

a = -4.9; b = 12.86; c = +40;
Δ = b2-4ac
Δ = 12.862-4·(-4.9)·40
Δ = 949.3796
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{-(12.86)-\sqrt{949.3796}}{2*-4.9}=\frac{-12.86-\sqrt{949.3796}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12.86)+\sqrt{949.3796}}{2*-4.9}=\frac{-12.86+\sqrt{949.3796}}{-9.8}
$