Answer:
Step-by-step explanation:

Cross-multiplying will give us the following:

Dividing both sides by
will give us our answer:

Answer: 6x+5y=28
Step-by-step explanation:
Looking at the first equation, we can tell that x stands for notebooks and y stand for pens. Since this talks about the total cost with the amount of products they bought, we can automatically eliminate the subtracting answer choices.
Now, we know that 6x+57=28 is the correct answer because Sonja bought 6 notebooks and 5 pens. This becomes 6x+5y.
Answer:
The first one is not a function
The second is a function
Third not a function
Fourth is a function
Step-by-step explanation:
Answer: x=5 y=6
Step-by-step explanation: 6y=3× +21
6y-6=2× +20
Opposite sides of the rectangle are equal
Substitute 3x +21 into 6y in the second equation.