Question

Tìm a,b,c 

1. a/4 = b/6 ; b/5 = c/8

và 5b + 3b - 3c = -536

Answer 1

\(\frac{a}{4}=\frac{b}{6}\)\(,\)\(\frac{b}{5}=\frac{c}{8}\)

\(\Rightarrow\left(a=\frac{2b}{3}\right)\)\(,\)\(\left(b=\frac{5c}{8}\right)\)

\(\Rightarrow3a=2b\)\(,\)\(8b=5c\)

\(\Rightarrow b=\frac{3a}{2}\)\(,\)\(c=\frac{12a}{5}\)

\(\Rightarrow a=10\)\(,\)\(b=15\)\(,\)\(c=24\)

Answer 2

\(\frac{a}{4}=\frac{b}{6}.\frac{b}{5}=\frac{c}{8}\)

\(\Rightarrow\left(3a=2b,8b=5c\right)\)

\(\Rightarrow b=\frac{3a}{2}.c=\frac{12a}{5}\)

\(\Rightarrow a=10,b=15,c=24\)

Answer 3

\(5b+3b-3c=-536\)

\(\Rightarrow8b-3c=-536\)

\(\Rightarrow8\left(b+67\right)=3c\)

\(\Rightarrow8b-3c+536=0\)

\(\Rightarrow c=\frac{8b}{3}+\frac{536}{3}\)

\(\Rightarrow\frac{8b}{3}+\frac{536}{3}\)

\(\Rightarrow b=3n+2\)\(,\)\(c=8n+184\)\(,\)\(c=8\left(\frac{b+67}{3}\right)\)\(,n\in Z\)