Variable $x$ cannot be equal to $0$ since division by zero is not defined. Multiply both sides of the equation by $50x$, the least common multiple of $x,50,5$.
$$50\times 200=x\times 80\times \frac{4}{5}$$
Multiply $50$ and $200$ to get $10000$.
$$10000=x\times 80\times \frac{4}{5}$$
Express $80\times \frac{4}{5}$ as a single fraction.
$$10000=x\times \frac{80\times 4}{5}$$
Multiply $80$ and $4$ to get $320$.
$$10000=x\times \frac{320}{5}$$
Divide $320$ by $5$ to get $64$.
$$10000=x\times 64$$
Swap sides so that all variable terms are on the left hand side.
$$x\times 64=10000$$
Divide both sides by $64$.
$$x=\frac{10000}{64}$$
Reduce the fraction $\frac{10000}{64}$ to lowest terms by extracting and canceling out $16$.
