For which of the following situations would the order that items are chosen not matter?

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative

Need solving this second acceleration problem.

If x = -2, then x 2-7x+10 equals a. 0 b.20 c.28