Question 604985
graphing---check to see if i wrote your problem down right
 x+y=4
 y-x=4 answer: y=4-x
               y=x+4

 x-3y=3       y=x/3-1

 x+3y=9       y=3-x/3

solve substitution"    7x+3y=15
                       x=7-5y     answer:y=17/16
                                          x=27/16