Variable $x$ cannot be equal to $\frac{1}{2}$ since division by zero is not defined. Multiply both sides of the equation by $5\left(2x-1\right)$, the least common multiple of $1-2x,5$.
$$-5\left(3-2x\right)=3\left(2x-1\right)$$
Use the distributive property to multiply $-5$ by $3-2x$.
$$-15+10x=3\left(2x-1\right)$$
Use the distributive property to multiply $3$ by $2x-1$.