Answer:
17
Explanation:
a = 10
b = -7
a - b --> 10 - -7 --> 10 - (-7) --> 10 + 7
10 + 7 = 17
The Answer is 17
The answer is not 3 because there are 2 minus signs next to each other, and that turn the first minus sign into a plus sign and the negative seven(-7) into a positive seven(+7 or just 7). This is why the answer is 17 and not 3.