我想問..
吾用QUADRATIC FORMULA//
可吾可以搵到有冇REAL ROOTS嫁..
eg:
(x-2)^2=x
呢個係咩roots呀?
real roots
2008-09-01 2:31 am
回答 (2)
2008-09-01 7:53 am
✔ 最佳答案
(x-2)^2=xx^2-4x+4=x
x^2-5x+4=0
(x-4)(x-1)=0
x=4 or x=1
如果唔用QUADRATIC FORMULA,我諗只能用圖解法!
2008-09-01 4:59 am
(x - 2)^2 = x
x - 2 = ±√x
x - √x - 2 = 0或x + √x - 2 = 0
(√x)^2 - √x - 2 = 0或(√x)^2 + √x - 2 = 0
(√x - 2)(√x + 1) = 0或(√x + 2)(√x - 1) = 0
√x = 2 或 √x = -1 或√x = -2 或 √x = 1
x = 4 或 1
x - 2 = ±√x
x - √x - 2 = 0或x + √x - 2 = 0
(√x)^2 - √x - 2 = 0或(√x)^2 + √x - 2 = 0
(√x - 2)(√x + 1) = 0或(√x + 2)(√x - 1) = 0
√x = 2 或 √x = -1 或√x = -2 或 √x = 1
x = 4 或 1
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080831000051KK02003