Why did the paper rip when the student tried to stretch out the horizontal axis of his graph

The depreciation per unit for a company

Pls! does anybody know a shortcut for answering these types of questions in the future?

Celeste wants to have her hair cut and permed and also go to lunch. she knows she will need $50. the perm cost twice as much as her haircut and she needs $5 for lunch. how much does the perm cost?