0
$\begingroup$

I know that a ≡ 0 mod 2 means that a = 2n for some n

similarly a ≡ -2 mod 4 means a = -2 + 4m for some m

so n = 2m - 1 ... I am not sure how to use this to show that a ≡ -2 mod 4 implies a ≡ 0 mod 2

Any suggestions?

  • 2
    `so n = 2m - 1` You just found the integer $n$ for which $a=2n\,$, which shows that $a$ is even. – 2017-02-23

1 Answers 1

3

You already have $a=-2+4m$. Simply factor out a $2$.