Answer: B. a + (-b) = 7
Explanation:
The answer is B. a + (-b) = 7. a + (-b) is the same thing with a - b.
A. a + b = -7
a - b = 7 means the differences of a and b is 7, choice A is talking about their sum, so it could not be true.
C. -a - b = 7
if you multiply -1 on both sides, you will get a + b = -7. Therefore, it will not be true.
D. b - a = 7
a - b = 7 means that a is 7 more than b. The choice d shows the opposite, which it states that b is 7 more than a. Therefore, it is not true.