Question

How do you combine like terms in `(7+ 4x + 9x ^ { 2} + 2x ^ { 3} ) + ( 3- 4x + 9x ^ { 2} - 2x ^ { 3} )`?

Answer 1

`18x^2+10`

Explanation:

To combine like terms you need to add terms which have exactly the same variables together.
Remove the brackets first. We cab just leave them out because a plus sign in front does not change the terms inside the bracket at all.

`7+4x+9x^2 +2x^3 +3-4x +9x^2 -2x^3`

Re-arrange the terms with the like terms together.

`color(red)(2x^3 -2x^3) color(blue)(+9x^2+9x^2)color(forestgreen)(+4x-4x) color(magenta)(+7+3)`

Simplify: The terms do not change, only the numbers change.

`color(red)(0x^3) color(blue)(+18x^2)color(forestgreen)(+0x) color(magenta)(+10)`