Answer:
Reason which completes the proof of step 4 is:
Identity property of addition
Step-by-step explanation:
-(a+b)+a= -b
= -a+ (-b)+a (distributive property)
= -a+a+(-b) (Commutative property of Addition)
= 0+ (-b) (Additive inverse property)
= -b (Identity property of addition)
(Identity property of addition says that if 0 is the identity element and a is any element
Then, a+0=0+a=a)
So, reason which completes the proof of step 4 is:
Identity property of addition
