In this task you will be given a list of lists, of numbers. For every inner list, you should multiply every number in that list and put the results in your answer. The output should be a list of numbers with the same length as the number of the lists in the input list.
[[-42, -20], [-50, -30, -27, 29, -19], [-39, 46], [28, -28, 50, 15]]