Question

is 9x to the power of 2 and 5x like terms ?

Answer 1

9x^2 and 5x are not like terms because 9x is being squared and 5x isn't.

Answer 2

9x and 5x would be like terms because they share the same variable, however because the 9x is raised to the second power, 9x^2 and 5x cannot be like terms. The short answer to your question is that no, 9x^2 and 5x are not like terms.