If they list out the x’s (like in B and C) and they have two of the same x’s, it is not a function. If they have those circles (like in D) and one x goes to multiple y’s, then it is also not a function. Hope this helps!
No, since when you multiply a number by 0, that means you are not adding that number to the sum which is 0. Since there is no addition going on, the answer is 0, so when you multiply any number by 0, the answer is 0.
