Given the expressions below, which of the following correctly solves for a + b and b - a?

a: 3x - 2

b: -6x - 7

the answers are in the image

If you would like to calculate A + B and B - A, you can do this using the following steps:

A = 3 * X - 2
B = - 6 * X - 7

A + B = (3 * X - 2) + (- 6 * X - 7) = - 3 * X - 9
B - A = (- 6 * X - 7) - (3 * X - 2) = - 9 * X - 5

The correct result would be B.