Answer:
Step-by-step explanation:
<h2> x = (7 + 3) x 4</h2>
For this case we must simplify the following expression:

We solve the operation of the second parenthesis, taking into account that different signs are subtracted and the sign of the major is placed:

We multiply:

We eliminate the parentheses:

We add similar terms, taking into account that equal signs are added and the same sign is placed:

Answer:
The simplified expression is: 
12^2=144
144 is divided by b which also is an odd interger, there only 2 numbers : 1 and 3
if b=3, a^2=48, then there will be no a available
if b=1 , a^2=144, then a is 12 and 12 can not be divided by 9
The answer is D
You can use a diffrent kind of ruler for math then you could find the answer.