Answer
a is the GCF
Work Step by Step
$a^{3}$+6$a^{2}$-11a
Factors of $a^{3}$=a$\times$a$\times$a
Factors of 6$a^{2}$=6$\times$a$\times$a
Factors of -11a = -1$\times$11$\times$a
There is one "a" in common -> a is the greatesr common factor.