M(x)=−2x^2 + 8x−3 and n(x)= 2x^3−4x. what is m(x)⋅n(x)?

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.