To balance this simply find the common denominator between the subscripts 2 and 3 in the ionic compounds, which is 6. Then place the correct coefficients in front of both CuCl2 and AlCl3, which are 3 for CuCl2 and 2 for AlCl3. Then place 3 in front of the Cu and 2 in front of the Al metal.
The final result is completely balanced equation.
