Grace was given the description “three less than the quotient of a number squared and nine, increased by eight” and was asked to evaluate it when n = 6. her work is shown below.

In order to evaluate this, we first write the correct expression:

The quotient is:
n²/9

Increasing this by 8

(n²/9) + 8

Three less than this is

(n²/9) + 8 - 3
(n²/9) + 5

Now, we evaluate this for n = 6

(6²/9) + 5
(36/9) + 5
4 + 5
9

The value of the expression at n = 6 is 9.

She will need 5/8 bags for each square yard.