Paul bought a soft and a sandwich for 9.90. what equation may be used to find the price of each item if the sandwich cost 3.5 times as much as the soft drink?

So, let's say the soft drink equals y and the sandwich equals x.

x + y = 9.9

The sandwich costs 3.5 times as much as the soft drink

x = 3.5y

Therefore, we can replace x with 3.5y since they're the same thing

3.5y + y = 9.9  <-- That's the equation :)

sorry, i can't understand your question. will later if you describe more clearly!

: )