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You and your friend are selling magazine subscriptions. You sold 8 fewer magazine subscriptions than your friends.
Together you sold 42 magazine subscriptions. Write a system of linear equations that represents this situation.
How many magazine subscriptions did you sell?How many magazine subscriptions did your friend sell?
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x - y = 8, (1)
x + y = 42. (2)
x = # of magazine subscriptions your friend sold;
y = # of magazine subscriptions you sold.
Always when you see such a system, do this: add equations (1) and (2).
By doing this way, you exclude one unknown and get a single equation for the other:
2x = 50 ---> x = = 25.
Thus your friend sold 25 magazine subscriptions.
Hence, you sold 25 - 8 = 17 magazine subscriptions.