Answer
$6y^2-54 = (6)~(y+3)~(y-3)$
Work Step by Step
The general form of factoring the difference of two squares is as follows:
$x^2-y^2 = (x+y)~(x-y)$
We can factor the expression by using the GCF and then factoring the difference of two squares:
$6y^2-54 = (6)(y^2-9)$
$6y^2-54 = (6)~(y+3)~(y-3)$