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.
[[-48, 9, 49, 5], [-34, 37, -16, 4, 37], [-40, 43, 40, 48, 31], [22, -12]]