Hi as you will see my maths is rubbish but I am trying to learn and would be most grateful for some help.

This is a basic algebra problem that I am trying to solve

x+3-k=6-3k

the answer is given as

X=3-2k

I got as far as

X-k=3-3k

so

X-k+k=3-3k+k

so to get X=3-2k

3-3 must equal 3, this I don't understand, I would have thought 3-3=0?