For this case we have the following system of equations:

To solve, we clear "x" from the second equation:

We substitute "x" in the first equation:

We clear the value of the variable "y":

We look for the value of the variable "x":

Thus, the solution of the system is given by:

Answer:

Option D
Answer:

Step-by-step explanation:
Let p represent cost of each drink.
We have been given that the medium pizza costs two times as much as one drink, so the cost of medium pizza would be
.
We are also told that the large pizza costs three times as much as one drink, so the cost of la pizza would be
.
We have been given that Mary wants to buy one large pizza, one medium pizza, and three drinks.
Since the cost of one drink is p, so cost of 3 three drinks would be
.
The total cost of one large pizza, one medium pizza, and three drinks would be 
Mary started with $30, so amount left after all of her purchases would be 30 minus total cost of all purchases.

Therefore, Mary will have
dollars left after making all of her purchases.
Answer:
distributive property
Step-by-step explanation:
The distributive property is described as
a(b + c) = ab + ac
5(12 - 4) = 5(12) - 5(4) ← is obtained using the distributive property
Sugar: x pounds
flour: 2x + 5 pounds
2x + 3(2x + 5) = 40
2x + 6x + 15 = 40
8x = 25
x = 3.125
-> a sack of flour is 3.125 + 5 = 8.125 pounds
I hope it‘s coorect
Hope this helps! Good luck!