7x^2/3 * 9/14x

7x^2/3 * 9/14x =9/2*x^(2/3)*x =(9/2)x^(5/3)

\(7x^{2/3}\cdot \dfrac{9}{14x}\\ =\dfrac{9}{2x^{1/3}}\)

Or you mean this one:

\(7x^{2/3}\cdot \dfrac{9}{14}x\\ =\dfrac{9x^{5/3}}{2}\)

And, if you mean this one:

\(\dfrac{7x^2}{3}\cdot \dfrac{9}{14}x\\ =\dfrac{3x^3}{2}\)

Also you may mean this one:

\(\dfrac{7x^2}{3}\cdot \dfrac{9}{14x}\\ =\dfrac{3x}{2}\)

You covered all the bases LOL