Expand: (a – 9)^2.
Note
Use (p - q)^2 = p^2 - 2pq + q^2. The last term is still positive because (-9)^2 = 81.
Expand: (a – 9)^2.
Use (p - q)^2 = p^2 - 2pq + q^2. The last term is still positive because (-9)^2 = 81.