i am not sure how to do this problem
-6y(8y to the fifth power)
It sounds like you are trying simplify (-6y)(8y5). If this is the problem then remember the following steps.
Multiply the coefficients: (-6)(8) = -48
Remember that y = y1
Multiply exponential expressions with the same bases: (y1)(y5) = y6 (add the exponents)
Answer = -48y6