I don’t know sorry I’m on the same one and can’t find it out
<h2><u>Solution</u></h2>

<h3>Hope This Helps You ❤️</h3>
Answer:
they don't respect the signs
Step-by-step explanation:
when you have a problem like the one above you have to put parentheses to the negative numbers either to add or subtract them, there is where the sign rule comes in
63 dollars 3 hours
21 dollars 1 hour