How to subtract and add polynomials

To subtract, first reverse the sign of each term we are subtracting (in other words turn "+" into "-", and "-" into "+"), then add as usual.

To add here is an example not sure if entirely right but here it is.

Start with:2x2 + 6x + 5 + 3x2 − 2x − 1.

Place like terms together:2x2+3x2 + 6x−2x + 5−1.

Which is:(2+3)x2 + (6−2)x + (5−1)

Add the like terms:5x2 + 4x + 4