Answer:
Add like terms
Step-by-step explanation:
You want to combine the squared, the variables, and the constants.
Combine -2x^2 and 7x^2 to get 5x^2
Then combine 8x and 4x which is 12x
Then combine -9 and +2 which is -7.
You should get 5x^2 + 12x - 7.
Keep in mind you can only combine like terms that are in the same equals barrier
For example: You can combine 8x + 3 + 2x = 0
but not 8x +3 = 2x +0 because they are on different sides of the equal sign.
