[latex]5q-7=\frac{2}{3}\ \ \ \ \ \ |add\ 7\ to\ both\ sides\\\\5q=7\frac{2}{3}\\\\5q=\frac{23}{3}\ \ \ \ \ \ |divide\ both\ sides\ by\ 5\\\\\boxed{q=\frac{23}{15}}[/latex]

[latex]5q^{(3} -7^{(3}=\frac{2}{3} \\ \\ 15q -21=2 \\ \\ 15q=2+21 \\ \\ 15q=23 \\ \\ \boxed{q=\frac{23}{15}}[/latex]