Amy: x skirts Betty: 2x skirts Carol: (2x) + 7 skirts If Amy has 18 less than Carol, than Carol's equation minus 18 equals Amy's equation: [(2x) + 7] - 18 = x +18 +18 (2x) + 7 = x + 18 - 7 -7 2x = x + 11 -x -x x = 11 Input the solution for x into the girls equation to double check. Amy: 11 Betty: 2(x) 2(11) =22 Carol: (2x) + 7 22 + 7 =29 Does Amy have 18 less than Carol? Carol - Amy = 18 29 - 11 = 18 18 = 18 the problem is solved