
Mark M. answered 08/23/16
Tutor
5.0
(278)
Mathematics Teacher - NCLB Highly Qualified
(-8) - 7 - (-9)
(-8) - 7 + 9 to subtract a number add its opposite
-8 - 7 + 9 ( ) not needed
-15 + 9 add/subtract from left to right
-6