Systems of Linear equations

Question

The denominator of a fraction is greater than its numerator by 9. If 7 is subtracted from both its numerator and denominator, the new fraction equals 2/3. What is the original fraction?

Answer 1

d = n + 7

(n - 7)/(d-7) = 2/3

Substitute:

(n-7)/(n + 7 - 7) = 2/3

(n - 7)/n = 2/3

n - 7 = 2n/3

3(n - 7) = 2n

3n - 21 = 2n

n = 21 This is the numerator

d = 28 tThis is the denominator