Why is $\displaystyle |5+2(x-1)| \ge |5-2|x-1||$?
Did they use some triangle inequality here? I don't see how they got that.
Nevermind, solved. Uses reverse-triangle inequality.
Why is $\displaystyle |5+2(x-1)| \ge |5-2|x-1||$?
Did they use some triangle inequality here? I don't see how they got that.
Nevermind, solved. Uses reverse-triangle inequality.