\(\frac{1}5x-\frac{2}3y=30\)
Plug in 15 for y.
\(\frac{1}5x-\frac{2}3(15)=30\)
2/3 of 15 is 10.
\(\frac{1}5x-10=30\)
Add 10 to each side.
\(\frac{1}5x=40\)
Divide each side by 1/5.
(dividing by a fraction is the same as multiplying by its reciprocal...flip 1/5...×5)
\(\boxed{x=200}\)
