What is the answer for m/12 - 5 = 7

Ineed to learn how to solve this problem

Will used 20 colored tiles to make a design in art class. 5/20 of his tiles were red. what is an equivalent fraction for the red tiles?

Afurniture store has 1,500 chairs in storage. a manager uses three delivery receipts to simulate samples to check 100 chairs and note the number of brown chairs. suppose the actual number of brown chairs is 1,080. about how many brown chairs are