Please, help me to determine the set A={x integer/x=(6n-7)/(2n+1), n integer}. Thank you!

1 Answer

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

In order to find out the elements of the set A, we have to notice that the property of the set is that all it's elements are integer numbers (x integer).

For x to be integer, (2n+1) has to be the divisor of the



If we divide the expression above, with (2n+1), the result will be:


But x=(6n-7)/(2n+1) and x integer, so, in order to obtain x integer, (2n+1) has to be a divisor of 10.


(2n+1)=1, 2n=0, n=0, x=(6*0-7)/(2*0+1)=-7/1=-7

(2n+1)=-1,2n=-2,n=-1, x=(6*(-1)-7)/(2*(-1)+1)=13

(2n+1)=2, 2n=1, n=1/2 not integer

(2n+1)=-2, 2n=-3, n=-3/2 not integer

(2n+1)=5, 2n=4, n=2,x=(6*(2)-7)/(2*(2)+1)=5/5=1

(2n+1)=-5, 2n=-6, n=-3, x=(6*(-3)-7)/(2*(-3)+1)=5

(2n+1)=10, 2n=9, n=9/2 not integer

(2n+1)=-10, 2n=-11, n=-11/2 not integer