公式與代入法

1. A=6x^3 如果x=2，求A。
Put x=2 into A=6x^3
A=6x^3
=6(2)^3
=6(8)
=48

2. H=4/m-n 如果m=1/2，n=7，求H。
Put m=1/2，n=7 into H=4/m-n
H=4/m-n
=4/(1/2)-(7)
=4/(-6.5)
=-8/13
P.S.樓上Q.2做錯



2011-03-08 20:45:15 補充：
To 樓上

2. sub m=1/2 ,n=7
H=4/(1/2-7)
=4/(-13/2)
=4x(2/-13)
=2(-13)←wrong
=-26

4x2/-13
4唔可以同2約

1) A=6X^3
A= (6)(8)
A= 48

2) 唔知你條題目想講咩

4
如果 H= --------
m-n

8
H = - ------
13

4
如果係 H= --- - n
m


H = 1

1. Sub x into 2,
A=6(2)^3
=6(8)
=48

2. sub m=1/2 ,n=7
H=4/(1/2-7)
=4/(-13/2)
=4x(2/-13)
=2(-13)
=-26