Question

Using the GCF you found in Part B, rewrite 72 + 81 as two factors. One factor is the GCF and the other is the sum of two numbers that do not have a common factor. Show your work.

Answer 1

The factors of 72 and 81 are

`\begin{gathered} 72=2^3\cdot3^2 \\ 81=3^4 \end{gathered}`

Therefore, their GCF is equal to 3^2=9

Then,

`72+81=9\cdot8+9\cdot9=9(8+9)`

The answer is 9(8+9).

The factors of 8 and 9 are

`\begin{gathered} 8\to2,4,8 \\ 9\to3,9 \end{gathered}`