Question and picture attached. Algebra2. Help Please!

Question

anonymous · Answer

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anonymous · Answer

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anonymous · Answer

A is 2x3, and B is 3x3. So, AB is going to be 2x3.

Eliminate choice B and D.

To calculate the first entry of AB, you multiply A's 1st row elements with the respective B's first column elements.

(1)(-1) + (-1)(2) + (2)(0) = -1 - 2 + 0 = -3.

Choice A's first element is not -3, so it must be choice C.

anonymous · Answer

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anonymous · Answer

This is a common strategy for solving math problems. It would waste time on an exam had you calculated the entire matrix.

anonymous · Answer

A 3x3 matrix multiplied by a 3x1 matrix results in a 3x1 matrix.

Choice A is the only one that is a valid mathematical equation.

anonymous · Answer

So choice A for the second question?

anonymous · Answer

Yes. Do you need an in-depth explanation? It took me forever to become comfortable with matrices haha.

anonymous · Answer

Its so confusing to me bc i feel like theres alot to remember lol youre explaination was plenty. thank you

anonymous · Answer

You're welcome!