Simplify (8x^4 + 3x^3 - 7x + 9) - (4x^4 -2x^3 + 2x^2 - 10) show your work and explain the steps. leave your answer in standard form.

(8x^4 + 3x^3 - 7x + 9) - (4x^4 -2x^3 + 2x^2 - 10)

we can get rid of the first brackets because there is nothing in front of them, and the second set can be removed by multiplying all the terms inside by -1

8x^4 + 3x^3 - 7x + 9 - 4x^4 + 2x^3 - 2x^2 + 10
Now collect like terms 
8x^4 - 4x^4 + 3x^3 + 2x^3 - 2x^2 - 7x + 9  + 10
and simplify
4x^4 + 5x^3 -2x^2 -7x + 19