Hi guys, i m just a begineer in number theory. While solving some questions ,i came across a doubt. The expression: a+bx here, gcd(a,b)=1 There always exists a value of x(where x is a integer) such that the above expression is equal to a prime number. Can anyone prove the above statement (if it is true). Also,please suggest some good book on number theory for begineers. Thanks in advance.