1 easy question

2012-07-25 2:04 am
if (x+3)^2-(x+1)(x-3)≡P(x+1)+Q,
find P and Q.

plz show step by step
thanks a lot!

回答 (2)

2012-07-25 2:13 am
✔ 最佳答案
If (x+3)^2-(x+1)(x-3)≡P(x+1)+Q,
find P and QSolP(x+1)+Q,
≡(x+3)^2-(x+1)(x-3)≡(x^2+6x+9)-(x^2-2x-3)≡8x+12≡8(x+1)+4P=8,Q=4
* P,Q如不是常數,則解無限多
2012-07-25 2:35 am
(x+3)^2-(x+1)(x-3)≡P(x+1)+Q

left=x^2+6x+9-(x^2-3x+x-3)
left=x^2+6x+9-(x^2-2x-3)
left=x^2+6x+9-x^2+2x+3
left=8x+12

right=P(x+1)+Q
right=Px+P+Q
rigth=Px+(P+Q)

8x=Px P+Q=12
P=8 8+Q=12
Q=4


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