Answer:
idk a or c
Step-by-step explanation:
Subtract original amount from new amount:
84 - 39 = 45
He bought 45 books.
The answer is 12!
Hope this helps! :D
------The answers got taken down :(------
X should be 7 after doing all the calculation.
Distribute first
a(b+c)=ab+ac
7y(8y-7)=56y^2-49y
now we have
56y^2-49y+46y
56y^2-3y
tada
