Answer:
w=15
Step-by-step explanation:
Subtract original amount from new amount:
84 - 39 = 45
He bought 45 books.
Answer:

Step-by-step explanation:
difference of a number and 9 means to subtract

twice that means multiply by 2

at least is greater than or equal to

The one that look exactly the same it the third one
you would divide both sides by 6 to get your answer. i hope this helps :)