※ 引述《jimmychengTW (同手同腳)》之銘言：
: 線型函數 f(x)=ax-b g(x)=bx-a 的圖形交於一點(a-b ,5) 則(a,b)
: a=b=-5 對嗎?
: 謝謝
ax - b = bx - a
=> (a - b)x = (b - a)
1. a - b = 0
=> f(x) = g(x) = ax - a
a(a - b) - a = 5
=> a = -5 = b
f(x) = -5x + 5 = g(x)
2. a - b =/= 0
x = -1
=> a - b = -1
a(-1) - b = 5
=> a + b = -5
=> a = -3, b = -2
f(x) = -3x + 2
g(x) = -2x + 3
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 111.249.186.33
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1494515495.A.962.html