If we were to do this equation how would I solve it

The sum of two numbers is 12 and their difference is 18 what are the two numbers

Ten members of balin's soccer team ran warm ups for practice. each member ran the same distance. their combined distance was 5/6 of a mile. to find the distance that each member ran, balin wrote the expression below.

Identify the expression equivalent to 4(x + x + 7) − 2x + 8 − 4 by substituting x = 1 and x = 2.