Answer:
The book store will receive 9 boxes
Step-by-step explanation:
Hope this helps<3
The bookstore receive 9 boxes.
it is 12
because 40 x 30
100
= 12
hello :
a(x) = 3x - 12 and b(x) = x-9, so
a[b(x)]=a(x-9) =3(x-9)-12
a[b(x)]=3x-9-12
a[b(x)]=3x+21
