$$\\7x^{1/3}=7*\sqrt[3]{x}\\\\
6x^{-4}=\frac{6}{x^{+4}}\\\\
12x^{-3/2}=\frac{12}{x^{+3/2}}=\frac{12}{x^{1+1/2}}=\frac{12}{x\sqrt{x}}$$
Here are more examples
http://web2.0calc.com/questions/indices-especially-negative-indices
$$\\7x^{1/3}=7*\sqrt[3]{x}\\\\
6x^{-4}=\frac{6}{x^{+4}}\\\\
12x^{-3/2}=\frac{12}{x^{+3/2}}=\frac{12}{x^{1+1/2}}=\frac{12}{x\sqrt{x}}$$
Here are more examples
http://web2.0calc.com/questions/indices-especially-negative-indices