If you mean
(3x-5)/6= (7x+4)/4 , then
12 x - 20 = 42 x + 24
and you can take it from there.
If you mean 3x - 5/6 = 7x + 4/4,
then the answer will be different.
Please use parentheses to clarify ambiguous algebraic statements such as the one you typed.