Question

Which student correctly translated the phrase “twice the sum of a number cubed and nine” and evaluated it for r = 3?

Antonio's work. 2 (r cubed + 9) = 2 (3 cubed + 9) = 2 (9 + 9) = 2 (18) = 36.
Jessica's work. 2 (r cubed + 9) = 2 (3 cubed + 9) = 2 (27 + 9) = 2 (36) = 72.
Maria's work. 2 + r cubed + 9 = 2 + 3 cubed + 9 = 2 + 27 + 9 = 29 + 9 = 38.
Mark's work. 2 + 3 r + 9 = 2 + 3 (3) + 9 = 2 + 9 + 9 = 11 + 9 = 20.

Answer 1

Your answer will be Jessica

Step-by-step explanation:

Answer 2

Answer: Jessica is correct

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Step-by-step explanation:

• Antonio is not correct because 3 cubed is not 9. Instead, it's 3^3 = 27. Note that 3^3 = 3*3*3 = 27. Another example would be 4^3 = 4*4*4 = 64. The good news is that he has the correct starting expression because the r^3+9 portion is the sum of r cubed and 9, then we double it.
• Jessica is correct. She has the correct starting expression and has evaluated 3^3 correctly. Also, the final answer 72 is correct as well.
• Maria doesn't have the correct starting expression.
• The same goes for Mark. His starting expression isn't correct.