For pi day, Jill sells 3 apple pies and 1 lemon for & 21. Jack sells 2 apple pies and 3 lemon pies for $28. What was the price of one apple pie

I'm guessing but not sure, wouldn't it be 7

A = Apple Pies

L = Lemon Pies

3A + 1L = 21

2A + 3 L = 28

Try to get one variable to the negative version of the other. Like this

(-3) 3A + (-3) L = (-3) 21

2A + 3L = 28

So now, it is:

-9A - 3L = - 63

2A + 3L = 28

Combine Terms.

-7A = - 35

A = 5

Therefore, One Apple Pie costs $5, and one Lemon Pie costs $6