Question

20. If least prime factor of x is 3 and least prime factor
of y is 7, the least prime factor of (x + y) is
(a) 2
(b) 3
(c) 7
(d) 21​

Answer 1

Answer:

2

Step-by-step explanation:

Given: The least prime Factor x is 3.

x belongs to integer.

so, x = 2n+1

Then, the least factor of y is 7.

y belongs to integer.

so, y = 2m+1

Here we have to find the least prime factor of

x+y

2n+1 + 2m+1 = 2(n+m+1)

let n+m+1 be taken as X

m+n+1 belongs to integer

2X belongs to integer.

so the least prime factor is 2.