Hi everyone. So, I was set the question Simplify δ_(ij) a_(jk) b_(l) given that a_(ij) = 3 And the options: 1) 3b_(l) 2) a_(ik) b_(l) 3) a_(jk) b_(i) I picked option 2). But this was marked wrong, stating that 1) was correct. I can see the reasoning behind it, but is this question misleading/legal? Because j is used as a Dummy Index in one equation, but a Free Index in another?