-30=-4.9x^2+20x+5

Solution for -30=-4.9x^2+20x+5 equation:

-30=-4.9x^2+20x+5

We move all terms to the left:

-30-(-4.9x^2+20x+5)=0

We get rid of parentheses

4.9x^2-20x-5-30=0

We add all the numbers together, and all the variables

4.9x^2-20x-35=0

a = 4.9; b = -20; c = -35;
Δ = b2-4ac
Δ = -202-4·4.9·(-35)
Δ = 1086
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{1086}}{2*4.9}=\frac{20-\sqrt{1086}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+\sqrt{1086}}{2*4.9}=\frac{20+\sqrt{1086}}{9.8}
$