Step-by-step explanation:
Hi, I think correct variant is B
(28÷7)+7=4+7=11
Let:
x = Chemistry textbooks sold
y = Physics textbooks sold
The textbook store sold a combined total of 260, so:

The number of chemistry books sold was three times the number of physics textbooks sold, so:

Let:

Replace (2) into (1):

Replace the value of y into (2):
Answer:
-1 = 4
0 = -2
1 = -8
5 = -32
Step-by-step explanation:
trust
X = -6y - 12
4x + 5y =-39
4x + 5y = -39
-4(-6y - 12) + 5y = -39
-4(-6y) + 4(12) + 5y = -39
24y + 48 + 5y = -39
29y + 48 = -39
29y = -87
y = -3
x = -6y - 12
x = -6(-3) - 12
x = 28 - 12
x = 6
(x, y) = (6, -3)
Answer:
The difference in price per ounce of the boxes is $0.03 or 3 cents.
Step-by-step explanation:
Divide each dollar amount by the ounces. The answer to $2.94 divided by 14 is 21 cents. $3.60 divided by 20 is 18 cents. Subtract 18 cents from 21 cents to get 3 cents.