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.
[[15, -20, -49], [8, -15, -37], [-23, 49, 47, -10], [-4, -47, 23, -28]]