Your answer would be -35.
For this case we propose a system of equations:
x: Let the variable representing the quantity of Granny Smith apples
y: Let the variable representing the number of Gala apples
According to the statement we have:

From the first equation we have to:

replacing in the second equation:

So, Carl bought 7 Gala apples
On the other hand:

So, Carl bought 12 Granny Smith apples
Answer:
Carl bought 7 Gala apples and 12 Granny Smith apples
What’s the question tho lol
Answer:
If you are finding the equation using two points then the answer is
y = −2 x + 1
If this does not help, just ignore honestly.