Q. 157:
We are given the following expression

Let us factor out the expression

We can apply the difference of squares formula as shown below

Notice that these are three consecutive integers (n-1), n, (n+1)
Since there are 2 consecutive integers, it must be divisible by 2.
Also, since there are 3 consecutive integers, it must be divisible by 3.
The LCM of 2, 3 is 6
Therefore, the largest number is 6 by which the given expression is divisible.