回答以下問題，加上清楚的列式!!!
1.Given that x+y = 39 and x : y = 4 : 9.
(a)For the expression x : y = 4 : 9, express x in term of y.
(b)Hence, find the values of x and y.
Maths!!!
2008-06-16 12:13 pm
回答 (2)
2008-06-16 12:33 pm
✔ 最佳答案
X:Y=4:9x/y=4/9
4y=9x
y=9x/4
9x/4=y
x=4y/9
x+y=x+9x/4=39
13x/4=39
13x=39x4
x=12
y=39-12
y=27
2008-06-16 12:39 pm
(a) x:y=4:9
x/y= 4/9
x=4y/9
(b) x + y = 39 --------x : y= 4 :9
x=39-y
Therefore: (39-y) : y = 4 : 9
(39-y)/y = 4/9
9(39-y) = 4y
351-9y = 4y
351= 4y + 9y
13y = 351
y= 27
Therefore : x= 12 because x+ y=39-------x=39-27
收錄日期: 2021-04-13 15:42:19
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