Question

If n is even, which of the following cannot be odd?

a) n + 3
b) 3n
c) n² - 1,
Can you please explain with some details?

Answer 1

b) 3n
well, first of all, you can try it out with numbers like 4,6,28...
3(4)
=12
3(6)
=18
3(28)
=84

also, you can disprove the other theories
a) 0+3=3 (odd)

b) 4^2-1=15 (odd)