Question

Gabriel determined that his total cost would be represented by 2.5x + 2y – 2. His sister states that the expression should be x + x + 0.5x + y + y – 2. Who is correct? Explain.

Answer 1

Gabriel and his sister are in apparent agreement. There is insufficient information to tell whether they are correct or not.

Gabriel's representation is a more compact form of his sister's representation, but they mean the same thing.*

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* In some computer applications, one gets a different result from computing 2.5x than from computing x + x + 0.5x. This has to do with the way numbers are represented in the computer and the way they are rounded during multiplication and/or addition. For the purposes of algebra, the expressions mean the same thing.

Answer 2

Answer:

Sample response: Both Gabriel and his sister are correct. The two expressions are equivalent. Gabriel’s sister just needs to combine her like terms to get the same expression as Gabriel.