0=4.9x^2-25

Solution for 0=4.9x^2-25 equation:

0=4.9x^2-25

We move all terms to the left:

0-(4.9x^2-25)=0

We add all the numbers together, and all the variables

-(4.9x^2-25)=0

We get rid of parentheses

-4.9x^2+25=0

a = -4.9; b = 0; c = +25;
Δ = b2-4ac
Δ = 02-4·(-4.9)·25
Δ = 490
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{490}=\sqrt{1*490}=\sqrt{1}*\sqrt{490}=1\sqrt{490}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-1\sqrt{490}}{2*-4.9}=\frac{0-1\sqrt{490}}{-9.8}
=-\frac{1\sqrt{490}}{-9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+1\sqrt{490}}{2*-4.9}=\frac{0+1\sqrt{490}}{-9.8}
=\frac{1\sqrt{490}}{-9.8}
$