Which expression represents the perimeter of the triangle?

Karena makes x dollars per hour working at the grocery store. She makes y dollars per hour working at the library. One week she worked 9 hours at the grocery store and 12 hours at the library. Which expression represents her total earnings for that week?

Short Response A square has side lengths (x - 9) meters. Write a linear expression in simplest form to represent the perimeter.

Write an expression in simplest form for the perimeter of the figure.

The number of students in each of the seventh grade homerooms that volunteer in the office are shown in the table. Use mental math to find the total number of students who volunteered. Explain.