What is y=2x+4 and 3x+y=9 substitution method

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?

The cost of turkey is directly proportional to its weight. if a 12-pount turkey costs $27, how much does a 13-pound turkey cost? a. $33.75 b. $36.00 c. $31.00 d. $32.50

Which container holds more, a half gallon milk jug or a 2 liter juice bottle