18) Let x be the number of coins in the pouch:
3x + 3 = 9; subtract 3 from each side:
3x + - 3 = 9 -3
3x = 6 . Now divide both side by 3:
x = 2 (in each pouch we have 2 coins)
19) SAME logic:
4x + 1 = 2x + 7; subtract 1 from each side:
4x + 1 - 1 = 2x + 7 - 1
4x = 2x + 6; now subtract 2x from each side:
4x - 2x = 2x + 6 - 2x
2x = 6 and x = 3 (each pouch contains 3 coins)