f.2數學 唔識點計

設女兒是 x :
3x - x = 36
2x = 36
x = 18

答:
女兒是 18 歲
philip 是 3(18)=54歲

x = 18
=.=

Let Philip's age is x and his daughter's age is y

x-y=36 and x=3y

Sub x=3y into x-y=36

3y-y=36
2y=36
y=18

Since x=3y

x=3x18
x=54

Let X be philip age;
Let y be philip daughter age;

"philip is 3 times as old as his daughter"
Therefore 3y = X ; (Eq1)

"if the difference of their ages is 36,"
Threfore X-y = 36; (Eq2)

Subsitute Eq1 into Eq2
3y - y = 36
2y = 36
y = 18

Put y = 18 into Eq 1
X = 3x18
X = 54

i.e. Philip is 54 years old and Philip daughter is 18

Let age of philip be x,his daughter be y
x-y=36------1
x=3y---------2
put 2 into 1
2y=36
y=18

put y=18 into 1
x=54

THUS,the age of philip is 54,his daughter is 18

Let Philip's age is x and his daughter's age is y

x-y=36 and x=3y

Sub x=3y into x-y=36

3y-y=36
2y=36
y=18

Since x=3y

x=3x18
x=54

So Philip is 56 years old and his daughter is 18 years old

2008-02-21 17:37:54 補充：
So Philip is 54 years old and his daughter is 18 years old

我想問是唔是二元一次式