Which pair of expressions are equivalent?

6 t + 5 + 2 t and 11 t + 5

p + 3 + 2 p and 5 t + 3

3 n + 7 and 4 n + 7

2 x + 2 + 7 x and 9 x + 7

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

What is the circumference of the pie