a). When Katherine was dividing the equation by 2, she handled the ' 2x '
correctly, and she handled the '16' correctly, but she forgot to divide the '7' by 2.
b). Here's what she should have done. I think this would be easier:
2x + 7 = 16
Subtract 7 from each side: 2x = 9
Divide each side by 2 : x = 4.5