Use inductive reasoning to predict the next Number in each sequence.

Question

1.3,7,11,15... i figure this to be 19 because each number following the first is a difference of 4.

2. 1,-2,4,-8 this is abit difficult for me. I am guessing the answer tobe 10. I cant'even explain how I ARRIVE AT 10 IF IT IS CORRECT CAN YOU HELP PLEASE? Thanks much

First is right.

On the second, multiply the last number by -2.

AH AH!
Thanks