Question

13. The numbers x, x + 2, x + 4 are all prime
so x is
(1) 3
(2) 2
(3) 11
(4) 17​

Answer 1

Answer:

One of XX, X+2X+2, and X+4X+4 must be divisible by 3. Because of this, all three can be prime only if one of them is 3.

X=3X=3 gives 3, 5, 7 which works.

X=1X=1 gives 1, 3, 5 does not work because 1 is not considered a prime.

X=−1X=−1 gives the even more ridiculous -1, 1, 3.

So, 3, 5, 7 is the only such triplet, although there are prime triplets of the form XX, X+2X+2, X+6X+6 or XX, X+4X+4, X+6X+6.

Answer 2

Answer:

Ans 1

Step-by-step explanation:

x= 3prime

x+2=3+2=5 prime

x+4=3+4=7 also a prime number