若(x-2):(x+6)=1:9則(4x-1):(12x-3)=? 不等式-1-5(2x-3)>=7+2(-3x-1)的最大整數解為?已知x與y成正比x=2時y=10x與y的關係式為?已知點A(3-2k,4k-1)在直線L:2x+5=0上且直線M垂直直線L於A點直線M的方程式為?

2016-08-08 7:46 am

回答 (2)

2016-08-08 8:16 am
✔ 最佳答案
1若(x-2):(x+6)=1:9則(4x-1):(12x-3)=?
Sol
(x-2):(x+6)=1:9
9(x-2)=x+6
9x-18=x+6
8x=24
x=3
(4x-1):(12x-3)
=(12-1):(36-3)
=11:33
=1:3

2 不等式-1-5(2x-3)>=7+2(-3x-1)的最大整數解為?
Sol
-1-5(2x-3)>=7+2(-3x-1)
-1-10x+15>=7-6x-2
-4x>=7-2+1-15
-4x>=-9
x<=2.25
最大整數解為2

3 已知x與y成正比x=2時y=10,x與y的關係式為?
Sol
設y=kx
10=k*2
k=5
y=5x

4 已知點A(3-2k,4k-1)在直線L:2x+5=0上且直線M垂直直線L於A點直線M的方程式為?
Sol
2(3-2k)+5=0
6-4k+5=0
4k=11
k=2.75
A(-1.5,10)
M:y=10
2016-08-08 8:19 am
1.
(x-2) / (x+6)=1/9
9(x-2) = x+6
9x-18 = x+6
8x = 24
x = 3

∴(4x-1):(12x-3)
= [4(3)-1] /[12(3)-3]
= 11/33
= 1/3

2.
-1-5(2x-3)≧7+2(-3x-1)
-1-10x+15≧7-6x-2
14-10x≧5-6x
14-5≧-6x+10x
9≧4x
x≦ 9/4 = 2.25
∴ x 的最大整數解 = 2

3.
x=2時y=10
=> y/x =10/2=5
=> y = 5x ...........[x與y的關係式]

4. 直線L :2x+5=0
L 的斜率 = ∞
M 丄 L , ∴M 的斜率 = 0

M 斜率 = (3-2k) /(4k-1) = 0
3-2k = 0
3 = 2k
k = 3/2
∴ A = (3-2k,4k-1) = (3-2(3/2),4(3/2)-1) = (0,5)
M的方程式 :
(y-5)/(x-0) = 0
y-5 = 0
即 y = 5


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