Variable $x$ cannot be equal to $0$ since division by zero is not defined. Multiply both sides of the equation by $75x$, the least common multiple of $x,75$.
$$75\times 125=x\times 25$$
Multiply $75$ and $125$ to get $9375$.
$$9375=x\times 25$$
Swap sides so that all variable terms are on the left hand side.
