Work Shown:
7y+3c=9y+12-2y+3
7y+3c=(9y-2y)+(12+3)
7y+3c=7y+15
3c=15
c = 15/3
c = 5
The steps above show that the y terms cancel. Solving for c leads to 5. If c is this value, then the original left and right hand sides are identical. Two sides being identical lead to infinitely many solutions. If [tex]c \ne 5[/tex], then there are no solutions for y.