Answer:
Equation is 3x + 4 = 22
x = 6
Number of weeks she read is 6.
Step-by-step explanation:
Let x be the number of weeks she read.
Total number of books = 22
Each week she reads 3 books.
After x weeks the number of books left unread = 4
Number of books read in x weeks = 3x
Total number of books = number of books read in x weeks + number of books left unread after x weeks.
22 = 3x + 4
3x = 18
x = 6
Hence number of weeks she read is 6.