x(-4.9x+75)=0

Solution for x(-4.9x+75)=0 equation:

x(-4.9x+75)=0

We multiply parentheses

-4x^2+75x=0

a = -4; b = 75; c = 0;
Δ = b2-4ac
Δ = 752-4·(-4)·0
Δ = 5625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5625}=75$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(75)-75}{2*-4}=\frac{-150}{-8}
=18+3/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(75)+75}{2*-4}=\frac{0}{-8}
=0
$