(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