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: [[10, 36, 12, -15], [2, -18], [30, -31, -42]]

[-64800, -36, 39060]