I would be interested, they help because they allow you to see how much you can use for whatever it is you need. An example would be how much money you can spend per month to still have enough for your bills
Answer:
3 one ofx+2 And 4th one x4
13 + 2x = 3
subtract 13 from both sides of the equation
2x = -10
divide by 2 on both sides
x = -5