5x+2y = 20
For every hardcover book (x) you will be charged 5$.
For every paperback book (y) you will be charged 2$.
The amount of both types of books you buy has to be under or equal to 20$
$2100 left the ATM ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Hey how are you doing today?
Answer: 
<u>Switch operations</u>
Before: 
After: 
Before you switch operation you remove the subtraction sign where -(16) is.