(25+4.9x)x=0

Solution for (25+4.9x)x=0 equation:

(25+4.9x)x=0

We add all the numbers together, and all the variables

(4.9x+25)x=0

We multiply parentheses

4x^2+25x=0

a = 4; b = 25; c = 0;
Δ = b2-4ac
Δ = 252-4·4·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-25}{2*4}=\frac{-50}{8}
=-6+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+25}{2*4}=\frac{0}{8}
=0
$