Simplify the expression -3r+7-3r-12

Just tell me how to set up the equation.

Apackage of orgainc strwberries costs $1.50 while there in season and $2.25 when not in season what the percent increase

The bottom of ignacio's desktop is 74.5cm from the floor. ignacios sits in his adjustable chair, and the tops of his legs are 49.3cm from the floor. each clockwise rotation of the knob on the chair raises ignacio's legs by 4.8cm. write an inequality to determine the number of clockwise rotations, r, ignacio could make with the knob without his legs touching the desk.