Answer:
n(x + y + z)
Step-by-step explanation:
The total number of apples bought is x+y+z. The total expense is the product of the cost and the number bought. If each one costs "n", then the cost is ...
n(x +y +z)
Answer:

Step-by-step explanation:
We can solve this system just by summing each side of the equation:
So, both left sides will be sum, and both right sides too.
The resulting expression will be:

Ordering and solving both sides:

Hence, the value to the system is 
It's important to combine both equation, because the exercise is asking for the solution of the system.
Answer:
D
Step-by-step explanation:
For this question, we know that x represents the thousands of square feet in the stadium. We also know that the stadium is 18 thousand square feet. Therefore, the amount of thousands of square feet, or x, is 18. We can then plug 18 in for x in the equation, getting

as our cost
Sam will need $20.42 if she wants to buy all three books.