Variable $x$ cannot be equal to $0$ since division by zero is not defined. Multiply both sides of the equation by $25x$, the least common multiple of $x,25$.
$$25\times 6=x\times 0.5$$
Multiply $25$ and $6$ to get $150$.
$$150=x\times 0.5$$
Swap sides so that all variable terms are on the left hand side.
$$x\times 0.5=150$$
Divide both sides by $0.5$.
$$x=\frac{150}{0.5}$$
Expand $\frac{150}{0.5}$ by multiplying both numerator and the denominator by $10$.
