1) the rule for #1 is is to subtract the small number from the big number so (15-4) (get rid of all the signs when doing this see how i took away the sign from 15) the answer is then 11 but you pit the sign of the bigger number since 15 is the bigger number and it has the negative sign you put the negative sign on 11 so the answer for 1 is -11
2) to solve -3*-5 you have to realize that they are both negative and the rule of multiplying negative integers is that a negative times a negative = a postive (weird but those are the rules) so -3*-5=15
