Answer
$\left\{0, 4\right\}$
Work Step by Step
Subtract $20x$ on both sides of the equation to obtain:
$5x^2-20x=0$
Factor out $5x$ to obtain:
$5x(x-4)=0$
Equate each factor to zero then solve each equation to obtain:
$5x=0 \text{ or } x-4=0
\\x=\frac{0}{5} \text{ or } x-4=0
\\x=0 \text{ or } x=4$
Thus, the solution set of the given equation is $\left\{0, 4\right\}$.
