Would you solve the equation 10=4(y-1) by using distributive property

Yes, it would look like the following:

10 = 4(y-1)

10 = 4y - 4

10 + 4 = 4y

14 = 4y

14/4 = 4y/4

3.5 = y

I hope this is right, and what you're looking for.

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18

126 maybe. sorry