Look at the picture beneath, then
scroll down to the question and click the correct Answer button.
Question
Let `phi: ZZ_12 to ZZ_12` such that `phi(a)` = 6a mod 12.
The image of all the odd numbers in `ZZ_12` is equal to 6.
Is it true that `ker(phi)` is equal to the set of even numbers
{0 , 2 , 4 , 6 , 8 , 10}
?