Definition: 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.
Input: [[31, -44, 12, 15, 48], [42, 40, -2], [18, 5, 31], [32, -23], [21, -40, 7, -13]]

[-11784960, -3360, 2790, -736, 76440]