What's m to the fourth power times 2m to he negative three power

First, multiply the implied "invisible one" on the first term by the 2 on the second term to get 2 as your coefficient. Then, multiply m^4 by m^-3 by adding your exponents and keeping "m" intact to get the second part of your answer, m. Now, put the two together to get a final answer, 2m.

2m you just subtract your exponents