Answer:
Correct option is (C)
Step-by-step explanation:
we are given that -Tim design a pair of shorts,S, and T-shirts,t.
Tim sell Sorts for $12 and T-shirts for $8 each.
Tim can work atmost 18 hours a day so we can write 
Time taken to design a T-shirt is 30 minutes and for Shorts, it is 45 minutes.

He must design 12 itesm each day, so we can write 
Further it can be written as

Also Tim can not design more than 30 items in one day, so we can write

Hence from the above equations , its claer that

Associative
** property I believe.
Answer:
x = 
Step-by-step explanation:
Since you cannot subtract -1 from 4x, you multiply 2 × 4x = 8x
Now, you have 8x - 1 + 3 = 7
Seperate the 8x from the other numbers
8x = 1 - 3 + 7 ---> 6
8x = 6
Now simplify
x =
<----- to reduce, divide the numerator and denominator by 2
Hence,
x = 
Infinitely many, because if you simplified the right side, it would equal the left side.