Given:
The expression is

The equivalent expression of this expression is

To find:
The missing value.
Solution:
We have,

The factor form of
is

The factor form 6b is

The common factors of
and
are
.


Taking out the highest common factors(HCF) from the given expression, we get

On comparing this with
, we get the missing value which is equal to
.
Therefore, the correct option is A.