Hello Amalia!
Here are the answers to your questions.
1. In such type of questions it is always better to assume some numbers.
First i would begin by taking n as an odd odd number...so let n = 1,then n(n+1)(n+2) becomes 1 x 2 x 3 which is = 6 and hence (a) is incorrect.Next if i take n = 2 it becomes 2 x 3 x 4 = 24 which is even although we have taken number to be even..so (b) and © are also incorrect.Now going back to this very example u can see it is also easily divisible by 3 althouygh n = 2 is even ..so (d) is also incorrect.HENCE THE CORRECT CHOICE IS (E).Which u can check by putting any value.
2. In second question , X x X = XY
therefore, X(X-Y) = 0 , giving either X = 0 or X = Y
Thus Correct choice is (A) .
These are basic questions and u can only master them with practice and a little application of a brain.Take up any good book of basics.U should just know the basic definiteion of Real,Integer numbers etc. and u should be able to do these questions easily.
Do post the questions that u r facing difficulty in .U might never know..it can appear in your test as well and can be other's difficuly as well.