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determinati abc stiind ca a/3=b/7=c/8 si 2a +5b-4c=108


Răspuns :

a/3=b/7=c/8=k

=>a=3k

b=7k

c=8k

=>2•3k+5•7k-4•8k=108

=>6k+35k-32k=108

=>41k-32k=108

=>9k=108

=>k=108/9=12

=>a=3•12=36

b=7•12=84

c=8•12=96

a/3=b/7=c/8

a=3k

b=7k

c=8k

2a+5b-4c=108

2×3k+5×7k-4×8k=108

6k+35k-32k=108

41k-32k=108

9k=108

k=108:9

k=12

a=3×12

a=36

b=7×12

b=84

c=8×12

c=96