If you would like to know which expression is equivalent to (9 * x - 3 1/8) - (7 * x + 1 3/8), you can calculate this using the following steps:
(9 * x - 3 1/8) - (7 * x + 1 3/8) = 9 * x - 3 1/8 - 7 * x - 1 3/8 = 2 * x - 25/8 - 11/8 = 2 * x - 36/8 = 2 * x - 4 4/8 = 2 * x - 4 1/2
The correct result would be A. 2 * x - 4 1/2.