✔ 最佳答案
You do the same steps as if you were doing integers:
Find out what goes into the highest power, multiply it through, subtract it, carry down anything unused, continue until complete:
. . . . . .__________
3x + 2 ) 12x² - x - 9
There's divide 3x by 12x², and you get 4x, so that goes up top, multiplied through 3x + 2, and then subtracted from 12x² - x - 9:
. . . . . .__4x______
3x + 2 ) 12x² - x - 9
. . . . . . .12x² + 8x
. . . . . . .-----------------
. . . . . . . . . . -9x - 9
And one more time, -3 3x's into -9x:
. . . . . .__4x_-_3__
3x + 2 ) 12x² - x - 9
. . . . . . .12x² + 8x
. . . . . . .-----------------
. . . . . . . . . . -9x - 9
. . . . . . . . . . -9x - 6
. . . . . . . . . . -----------
. . . . . . . . . . . . . .-3
-3 is our remainder, so that becomes a fraction -3/(3x + 2)
So your final answer is:
4x - 3 - 3/(3x + 2)