Charles claim that (3,-3) is the solution and Destiny claim that the solution is (-1,5) . Who is correct and why ?

Answer:
Both are correct because both equations are the same rendering infinite answers on the line. Both points fall on the line.
Step-by-step explanation:
First, convert to y=mx+b format.
6x+3y=9 is the same as y=-2x+3
Graph your lines then plot your points
Hope that helps