Jawabanmu

2014-09-05T19:28:05+07:00
 \frac{a}{b} +  \frac{c}{d} = 12

 \frac{ad+bc}{bd} = 12

ad+bc = 12bd

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 \frac{a}{c} +  \frac{b}{d} = 18

 \frac{ad+bc}{cd}= 18

ad+bc = 18cd

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12cb = 18cd -----> dibagi dengan 6d

2c = 3b
c = 3b/2

c/b = 3/2