Which equation can be used to find the perimeter of the rectangular chalkboard

Question 5 spring semester final exam math evaluate

Find the interior angle of a regular polygon which has 6 sides

What are the interpretations of the line 3x - 15y = 60? x-intercept y-interception a: x 20 - y -4 b: x 5 - y 20 c: x -3 - y 15 d: x -4 - y 20