Regular time:
wage: $18/hour * 40 hours = $720
Over time:
1.5 * $18/hour * number of hours over 40
number of hours over 40 = x - 40
wage = 1.5 * 18 * (x - 40) = 27(x - 40) for x ≥ 40
Total wage:
wage = $ 720 + 27 ( x - 40) ; x ≥ 40
wage = $720 + 27x - $27*40 = 27x + 720 - 1080 = 27x - 360
Answer: 27x - 360; x ≥ 40
