Answer
11/18
Work Step by Step
You have to get the fractions to their least common denominator. 9x2 is 18. 6x3 is 18. 18 is the LCD. Multiply the numerators by the same number the denominators are multiplied by.
So 7/9 becomes 14/18 and 1/6 becomes 3/18, then subtract to get 11/18.