Answer:
4
Step-by-step explanation:
There are two ways of going about this problem. One could simply substitute every given answer and simplify to see if it makes a true statement. Conversely, one could solve the given equation with inverse operations. In this case, it is easier to solve with inverse operations.
Undo parenthesis,
a + (-7) + 3 = 0
a - 7 + 3 = 0
Simplify,
a - 7 + 3 = 0
a - 4 = 0
Inverse operations,
a - 4 = 0
+4
a = 4
