What is 2+2=? adding letters for extra characters​

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*

A6 ounce bottle of dressing costs $1.56 a 14 ounce bottle costs $3.36 a 20 ounce bottle costs $5.60 which has the lowest cost per ounce