Answer:
[tex]a^{n}[/tex](1 + a + a²)
Step-by-step explanation:
consider the rule of exponents
[tex]a^{m}[/tex] × [tex]a^{n}[/tex] = [tex]a^{(m+n)}[/tex]
given [tex]a^{n}[/tex] + [tex]a^{n+1}[/tex] + [tex]a^{n+2}[/tex]
Take out the common factor [tex]a^{n}[/tex]
= [tex]a^{n}[/tex](1 + a + a²)