This I can solve.
Find a common denominator for the solution and the problem.
15 is the first common denominator.
3*5=15
5*5=25
x=25
Here's another method, h7......when two fractions are equal, their cross-products are equal
This implies that
3 * x = 5 *15
3x = 75 divide by 3 on both sides
x = 25 .... just as you found.....!!!