Hi...
Brand new here. Have 2 confusing math problems.

1. Which of the following is not a subset of A if A = (-3, -2, -1, 1, 2, 3, 4,5,6,7}?

1. {1,3,6,7}
2. {0,2,4,6}
3. {-2,-1,0,1,2}
4. {-1,3,5,6,7}

Couldn't the answers be 2 and 3 because they both contain the number 0 and Set A doesn't contain a zero? Or is the obvious escaping me?


Problem 2...

Express the product as a trinomial in simplest terms: (2x-3)(x+4)

I did the foil method and came up with 2xsquared + 8x - 3x -12 and subtracted the 3x from 8x and got... 2xsquaared +5x -12.

BUT... aren't the factors in 12 supposed to add up to the middle number? Am I missing something on this one?

I feel like I'm kind of starting to grasp the topics, but there are still a few things I'm unsure of.

Any help would be greatly appreciated. Thanks!

Hey where are you from? I am a 2nd year civil structural engineering student in australia and I don't think I have any idea on what your trying to solve. I might be able to help u...

Hi... I'm from New York. These are two algebra homework questions.

Problem 1: what is a subset. Simply, the set whose all the elements are already contained in another set. For example, 'human' is a set and 'male' or 'female' is a subset, because all the males are humans and so as females. Is that OK? Hope you have got your answer.

Problem2: your answer is perfect. What problem are you facing with this? Can you detail?

Your second question looks right to me.

So does your first question, but I have never studied set theory beyond the basics.

I found this sentence in wikipedia: If every member of set A is also a member of set B, then A is said to be a subset of B.

I would argue that your answer to the first question is also correct (it also makes sense to me logically!).

Yes, both his answers are correct. Explanation was provided to make him feel confident about it.

Thank you.

IN the first question, answer 2, 3 and 4 are correct.

Subset means that the secong groups based on the first excluding some elements.

In other words, A is subset of B, if the intersection of A and B is equal to A.

Luis

Quote:

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Originally Posted by luisnevesfct

IN the first question, answer 2, 3 and 4 are correct.

Subset means that the secong groups based on the first excluding some elements.

In other words, A is subset of B, if the intersection of A and B is equal to A.

Luis

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But then... 2 and 3 have '0' listed, which is not found in the intersection of 2 and A, nor 3 and A. So, 2 and 3 are the ones which are NOT the subset of A.

For number two, you consider the factors of the last term (which is independent of x) when you are factorising the trinomial, not when you're expanding.

You are right, of course. The zero elluded me...

2 and 3 are not subsets

Luis