Question

Is this proof correct ?

​

Answer 1

Answer:

Correct calculation, but incomplete proof

Step-by-step explanation:

Any proof should be universal, means applicable to all cases.

It is correct, but this proof is valid only for Universal set of x,y,z.

in that also, there can be cases where A∩B =Φ and A=B. In this cases also, this rule apply. but your proof does not cover these situations.

what if U = {a1,a2,a3......,an} (n number of elements)?

this rule you are proving is valid for n elements also. but your proof does not show how it is correct for n elements.