Answer:
$-8
Explanation:
Subtract 3 from 7 for the first day. She has $4 left
Subtract 3 from 4 for the second day. She has $1 left
Subtract 3 from 1 for the third day. She has $-2 left
Subtract 3 from -2 for the fourth day. She has $-5 left
Subtract 3 from -5 for the fifth day. She has $-8 left in her lunch account