Answer:
40
Step-by-step explanation:
Let n represent the integer. Then the increase can be written as ...
n + (-12) = 28
We can add 12 to both sides of this equation:
n + (-12) + (+12) = 28 +12
n + 0 = 40 . . . . . . -12 and 12 total to zero; 28 and 12 total to 40.
n = 40
The integer is 40.