Answer: m=19
Explanation:
First you cross multiply the two fractions. So you get 9*m = 57*3.
When you put 57*3 in a calculator you get 171. So the equation is 9m=171 and then to isolate the x you divide by 9. So when you put 171/9 in a calculator you get 19. So the correct answer is C. 19.