Your friend asks you to check their work. You see the expression 3(15−9)2 + 2 ⋅5

Question

Your friend asks you to check their work. You see the expression 3(15−9)2 + 2 ⋅5

simplified in the following way:

Original Problem: 3(15−9)2 + 2 ⋅ 5
Step 1: 3(6)2 + 2 ⋅5
Step 2: 3(36)+ 2 ⋅ 5
Step 3: 108 + 2 ⋅ 5
Step 4: 110 ⋅ 5
Step 5: 550
Part A: Explain, using complete sentences, in which step and what specifically your friend's error was.

Answer 1

Your friend made an error in Step 4. In that step, they multiplied 110 by 5 instead of adding it. Instead of multiplying, they should have added 110 and 5 to get the correct answer.

Answer 2

In Step 4, your friend made an error. They incorrectly multiplied 110 by 5 instead of adding it to 2 multiplied by 5. This mistake led to an incorrect final answer of 550.

Answer 3

Your friend asks you to check their work. You see the expression 3(15−9)2 + 2 ⋅5

Your friend made an error in Step 4. In that step, they multiplied 110 by 5 instead of adding it. Instead of multiplying, they should have added 110 and 5 to get the correct answer.

In Step 4, your friend made an error. They incorrectly multiplied 110 by 5 instead of adding it to 2 multiplied by 5. This mistake led to an incorrect final answer of 550.

Your friend made an error in Step 4. Specifically, their mistake was multiplying 110 by 5 instead of adding 110 and 5.