8(x + 7) + 8 divided by 3(x + 5) + 9

How can you tell when x and y are not directly proportional?

Determine if the outside temperature is a function of the time of day or if the time of day is a function of temperature and explain why or why not.

The students at jefferson middle school are raising money for a charity by selling t-shirts and hats. the number of t-shirts sold was 3 times the number of hats. the profit was $5 for each t-shirt sold and $2.50 for each hat sold. the students raised $840 for the charity. they used the system below to analyze their success and found the solution to be (144, 48). 5x+2.50y=840 x=3y how much did they earn from t-shirt sales?