Final answer:
The price of the book increased by $3, calculated by subtracting the original price of $19 from the new price of $22.
Step-by-step explanation:
The question involves solving a simple linear equation to determine the change in the price of a book. Liz observed that the price of a book increased from $19 last week to $22 this week.
To find the increase in price, represented by p, we can set up the following equation: 19 + p = 22.
Solving for p, we subtract 19 from both sides of the equation, which gives us p = 22 - 19, which simplifies to p = $3.