Answer
$3(1+3x)(1-3x)$
Work Step by Step
Factor out $3$.
$\begin{align*}
3-27x^2&=3(1-9x^2)\\
&=3[1-(3x)^2]
\end{align*}$
Use special formula $a^2-b^2=(a+b)(a-b)$. where $a=1$ and $b=3x$ to obtain:
$3-27x^2=3(1+3x)(1-3x)$
Hence, the completely factored form of the given expression is $3(1+3x)(1-3x)$.
