I've been trying that but I just can't seem to reduce to anything doable. I've got it down to row echelon form, but I'm left with the bottom line of [0 0 -k^2+2k+3|-k-3}
I don't know if I've done something wrong, but with that last line I just can't solve it.
Can someone help me out here or at least give me a push in the right direction? This question is doing my head in...