First I wold simplify the expressions by combining like terms so #1 becomes 9x-1 and #2 becomes 9x-1
Once you’ve done this you can see that the two expressions are actually the same and therefore equal to each other.
The best description of the equivalency would be D
Just because the sum of the constants are equal doesn’t mean the expressions are. There could be different amounts of the variable (that’s why you should always simplify )