(a-x) (b-x) (c-x) (d-x)........(z-x)=????

Let N = (a-x) (b-x) (c-x) (d-x)........(z-x)

Then, one of the terms of N is (x-x) which equals 0. Since, 0 when multiplied by any number is always zero, it follows that N=0.

Consequently, the required value of the given expression is zero