When makeing the chart, how do you determine which one in the number of coins graph gets "x" and which one gets "#-x"? Such as: Anthony has a total of 30 dimes and quarters worth $5.70. How many of each type of coin does he have? Do I make Quarters=30-x and Dimes=x or Dimes=30-x and quarters=x? I don't know how to determine which way. Also I get different answers depending one which way I put it. Thanks for any help on this.
Here is an example of one I am saying: