1. (9z+8)²
2. (9z+8)(9z+8)  An item raised to the second power is that item multiplied times itself
3. (9z+8)9z + (9z+8)8  Using the distributive property
4. 9z(9z+8) + 8(9z+8)  Simply rewriting
5. 9z*9z + 9z*8 + 8*9z + 8*8  Using the distributive property again
6. 81z² + 72z + 72z + 64          Doing the multiplcations
7. 81z² + 144z + 64                 Combining like terms

Hope this helps,

Steven

               (9z + 8)² = (9z + 8)·(9z+ 8)

      (9z+ 8)(9z + 8) = 9z·9z + 9z·8 + 9z·8 + 8·8

                             = 9z² + 72z + 72z + 64

                             = 9z² + 144z + 64

Thus,

          (9z + 8)² = 9z² + 144z + 64