how

You simplify an expression by combining all like terms.

 

For example, given the expression 3x^2 - 2 + 5x + 3 - x^2 + 2x + 13,

you could first combine all the constant terms:

 

3x^2 - 2 + 5x + 3 - x^2 + 2x + 13

3x^2 + 5x - x^2 + 2x - 2 + 3 + 13

3x^2 + 5x - x^2 + 2x + 14

 

Then you could combine the x terms:

 

3x^2 + 5x - x^2 + 2x + 14

3x^2 - x^2 + 5x + 2x + 14

3x^2 - x^2 + 7x + 14

 

And finally the x^2 terms:

 

3x^2 - x^2 + 7x + 14

2x^2 + 7x + 14

 

2x^2 + 7x + 14 is the simplified expression of 3x^2 - 2 + 5x + 3 - x^2 + 2x + 13.