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Daca 3a/5b=1/2,calculati 2a+3b/8a-4b

Răspuns :

3a/5b = 1/2⇒a=5b/6
2a + 3b/ 8a-4b=(2*5b/6+3b)/(8*5b/6-4b)=5b+9b/20b+12b=14b/8b=14/8=7/4
[tex]\frac{3a}{5b}=\frac{1}{2}\Rightarrow 6a=5b \Rightarrow \frac{6a}{5}=b \Rightarrow \frac{a}{b}=\frac{5}{6} \Rightarrow \frac{a}{5}=\frac{b}{6}=k \Rightarrow a=5k,b=6k\\ \frac{2a+3b}{8a-4b}=\frac{10k+18k}{40k-24k}=\frac{28k}{16k}=\frac{7}{4}[/tex]