Answer: 4 books
Explanation:
x = minimum number of book
Leslee
= 3x (bought 3 times the minimum)
Denise
= x + 7 (bought 7 more than the minimum)
Together
= (3x) + (x + 7)
(3x) + (x + 7) = 23 (books they bought together)
3x + x + 7 = 23
3x + x = 23 - 7 (isolate the like variables together)
4x = 16 (divide both sides by 4)
x = 4
4 is the minimum number of books
To check:
3(4) + (4+7)
12 + 11 = 23