Answer: -5a²b⁵c³
Step-by-step explanation: 5ab⁴c can be thought of as 5a¹b⁴c¹ and in the second part of the problem, since there is no coefficient on -a¹b¹c², we can give it a coefficient of 1.
Now simply multiply the coefficients
and add the exponents to get -5a²b⁵c³.