Answer:
[tex]16{a}^{2}-72a+81[/tex]
Step-by-step explanation:
1) Use Square of Difference:[tex]{(a-b)}^{2}={a}^{2}-2ab+{b}^{2}.[/tex]
[tex]{(4a)}^{2}-2\times 4a\times 9+{9}^{2}[/tex]
2) Use Multiplication Distributive Property: [tex]{(xy)}^{a}={x}^{a}{y}^{a}[/tex]
[tex]{4}^{2}{a}^{2}-2\times 4a\times 9+{9}^{2}[/tex]
3) Simplify [tex]{4}^{2}[/tex] to 16
[tex]16{a}^{2}-2\times 4a\times 9+{9}^{2}[/tex]
4) Simplify [tex]{9}^{2}[/tex] to 81
[tex]16{a}^{2}-2\times 4a\times 9+81[/tex]
5) Simplify [tex]2\times 4a\times 9[/tex] to 72a.
[tex]16{a}^{2}-72a+81[/tex]