a :b=3:4,b:c=5:6,则a:c=( ):( )

若a:b:c=4:5:6则2a+3b-c/2a-3b+c= {A+2B-3C=4,5A-6B+7C=8}求代数式A:B:C 2A-3C／A+2B 已知A:B=5:3,B:C=7:4则A:B:C= a：b=2：5,b：c=3：4,则a：b：c= a/3=b/4=c/5 a+b-c=6 a= b= c= a+2b+3c=5,4a+3b+2c=10,则a+b+c=?, a+2b+3c=5 3a+2b+c=-4则a+b+c等于? A/4=B/5=C/6求2A+3B-C/A+B+C 已知a-b/2=b-2c/3=3c-a/4.求5a+6b-7c/4a-3b+9c 4b+a=6a=5c ,则a:b:c是多少? (a-b-c)(b+c-a)(c-a+b)= 已知5a+6b=c-2b=-a-4b,则a:b:c=