Tara solved the following problem by doing the work shown. Which property did she use? (-2 · -8) · 9 = -2 · (-8 · 9) = -2 · -72 = 144 associative property of multiplication identity property of multiplication commutative property of multiplication

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?