F.4 MATHS
2013-11-14 10:46 pm
Consider the graph of y = -x^2 + 20x - 18. Rewrite the function in the form y = a(x - h)^2 + k
回答 (3)
2013-11-14 11:34 pm
✔ 最佳答案
y = -x² + 20x - 18y = -[x² - 2(x)(10)] - 18
y = -[x² - 2(x)(10) + 10²] + 10² - 18
y = -(x - 10)² + 82
2013-11-14 15:35:46 補充：
where a = -1, h = 10 and k = 82
2013-11-14 16:49:45 補充：
更改題目後的解法：
y = -2x² + 20x - 18
y = -2[x² - 10x] - 18
y = -2[x² - 2(x)(5) + 5²] + 2*5² - 18
y = -2(x - 5)² + 32 ...... (答案)
在答案中： a = -2, h = 5, k = 32
參考: micatkie, micatkie, micatkie
2013-11-15 12:43 am
y = -2x^2 + 20x - 18
= -2 (x^2 -10x) -18
= -2 (x^2 -10x+25-25) -18
= -2 (x^2 -10x +25)+50 -18
= -2 (x -5)^2 +50 -18
= -2 (x -5)^2 +32
so that a=-2, h=5, k=32
= -2 (x^2 -10x) -18
= -2 (x^2 -10x+25-25) -18
= -2 (x^2 -10x +25)+50 -18
= -2 (x -5)^2 +50 -18
= -2 (x -5)^2 +32
so that a=-2, h=5, k=32
2013-11-15 12:36 am
唔好意思呀, miracle~
題目更新了~
題目更新了~
收錄日期: 2021-04-13 19:49:00
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131114000051KK00100