Hi Everyone,
I am working on an inequalities question that involves the following inequality:

x + 3 < n – 1

In the answer exlanation the inequality is converted to the following:
x + n < 2n – 4

When doing the math I see how these 2 inequalities are equal, but how would I quickly know that x + 3 < n – 1 is equal to x + n < 2n – 4 without wasting time on the problem?

Any help/suggestions would be great.

Thanks