Answer
$(4k-9)(3k^{2}-10)$
Work Step by Step
$12k^{3}=2.2.3.k.k.k$ and $27k^{2}=3.3.3.k.k$
Hence, $GCF=$$3.k.k=3k^{2}$
$40k=2.2.2.5.k$ and $90=2.3.3.5$
Hence, $GCF=2.5=10$
After grouping:
$=(12k^{3}-27k^{2})-(40k-90)$
$=3k^{2}(4k-9)-10(4k-9)$
$=(4k-9)(3k^{2}-10)$