It's the letter D hope it helps
Answer:
The sale price is 
The expression is 
Step-by-step explanation:
we know that
The sale price is equal to subtract the discount price from the original price
The discount price is equal to multiply the original price by the percent discount in decimal form
Let
x ----> the sale price
y ---> discount price
----> percent discount in decimal form


substitute

therefore
the expression is

Answer:
27 I think just divide 81 by 3
Answer:
19 ft
Step-by-step explanation:
The perimeter of a rectangle is given by ...
P = 2(L +W)
Filling in the given values, we have ...
78 = 2(20 +W)
39 = 20 +W . . . . . divide by 2
19 = W . . . . . . . . subtract 20
The width of the rectangular pen is 19 feet.