Which expression is equivalent to 9 x squared minus 2 y + 3 x squared minus 3 y?
6 x squared minus y + 6 x squared minus 5 y
6 x squared minus y + 3 x squared minus 4 y
10 x squared minus 4 y + 2 x squared minus y
11 x squared + 2 y + x squared minus 3 y