Question 799203
2(7 + x) = 42
2(7) + 2(x) = 42
14 + 2x = 42
14 - 14 + 2x = 42 - 14
2x = 28
2x/2 = 28/2
x = 14

check:
2(7 + 14) = 42
2(21) = 42
42 = 42