x+5y=3 (1)

x=9-5y (2)
What is the solution of the system?
(-3,6/5)
is this correct?

x+5y=3 (1)

x+5y=9 (2) by transposing the 5y term
Since the two equations are identical on the-left-hand side and different on the right-hand-side, there is no solution because the system is inconsistent.
Perhaps you may want to check for typos.