Answer
$(4x+3)^2$
Work Step by Step
Rewrite $24x$ as $12x+12x$.
$16x^2+24x+9=16x^2+12x+12x+9$
Group the first two terms together and the last two terms together:
$=(16x^2+12x)+(12x+9)$
Factor out the GCF in each group.
$=4x(4x+3)+3(4x+3)$
Factor out $(4x+3)$.
$=(4x+3)(4x+3)$
$=(4x+3)^2$
Hence, the completely factored form of the given expression is $(4x+3)^2$.
