I am having trouble with what the yellow box next to 12 is supposed to be

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

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.

Which number completes the system of linear inequalities represented by the graph? y > 2x – 2 and x + 4y >