Respuesta :

3. 19 + x > = 39
      x > = 39 - 19
      x > = 20

4. 20x > = 1800
    x > = 1800/20
    x > = 90

5. 83 + x > = 180
    x > = 180 - 83
    x > = 97

6. sorry..not able to do this one...cannot read the question....cannot see how much the shipping costs.