If a is known to be greater than 1, simplify A-1 + A + 2 Then summarize the solution skills (inequality, which I don't quite understand)

If a is known to be greater than 1, simplify A-1 + A + 2 Then summarize the solution skills (inequality, which I don't quite understand)

A-1 + A + 2
=a-1+a+2
=2a+1.

If a is less than 0 and B is greater than 0, then A-B + A + B is simplified

A-B + A + B
The discussion is divided into three situations
1. When a = B, A-B + A + B = B-A
2. When a < B, A-B + A + B = B-A + A + B = 2B
3. When a > b, A-B + A + B = B-A + (- a-b) = - 2A

When a is greater than B and greater than 0, simplify a minus B minus a

Because a > b > 0, so | A-B | = A-B, | a | = a, so the original formula = A-B-A = - B