Answer:

n = 49/15 or 3 4/15

Step-by-step explanation:

convert the mixed number to an improper number

21/5 ÷ 9/7 = n

to divide by a fraction, multiply by the reciprocal of that fraction.

21/5 × 9/7 = n

reduce the numbers with the greatest common factor 3

7/5 × 7/3 = n

multiply the fractions

49/15 = n

swap the sides of equations

n = 49/15

alternate form

n = 49/15 or 3 4/15