23設A B為兩多項式 https://www.flickr.com/photos/101292575@N06/21264522632/in/dateposted-public/?
回答 (2)
2015-09-11 6:44 am
✔ 最佳答案
23.A + 3B = 12x² + 3x - 11
(27x² + 9x - 29) + 3B = 12x² + 3x - 11
3B = 12x² + 3x - 11 - (27x² + 9x - 29)
3B = 12x² + 3x - 11 - 27x² - 9x + 29
3B = -15x² - 6x + 18
B = (-15x² - 6x + 18)/3
B = -5x² - 2x + 6
A + 5B
= (27x² + 9x - 29) + 5(-5x² - 2x + 6)
= 27x² + 9x - 29 - 25x² - 10x + 30
= 2x² - x + 1 ...... 答案選(C)
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