Answer:
118
Explanation:
Part A:
My friend's error is in Step 4, where they multiply 110 by 5 instead of adding 110 and 2 • 5.
Part B:
Step 1: 3(15-9)² + 2 • 5
Step 2: 3(6)2 + 2 • 5
Step 3: 3(36) + 2 • 5
Step 4: 108 + 2(5)
Step 5: 108 + 10
Step 6: 118
Therefore, the correct simplified expression is 118.