Answer:
her first mistake was on line 3.
line 1: 80 + [2(3 1/2 + 1 1/2)]
line 2: 80 + [2(5)]
line 3: 80 + 10
line 4: 90
Explanation:
on line 3 she added 80 + 2, but she should have multiplied 2 by 5. the correct steps would be:
line 1: 80 + [2(3 1/2 + 1 1/2)]
line 2: 80 + [2(5)]
line 3: 80 + 10
line 4: 90