Question

Tìm y, biết:              7 : (  \(\dfrac{3,8xy-57}{19}\)+ 3) = 1,75

Answer 1

\(7:\left(\dfrac{3,8\times y-57}{19}+3\right)=1,75\)

\(\Rightarrow\left(\dfrac{3,8\times y-57}{19}+3\right)=7:1,75\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}+3=4\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}=4-3\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}=1\)

\(\Rightarrow3,8\times y-57=1\times19\)

\(\Rightarrow3,8\times y-57=19\)

\(\Rightarrow3,8\times y=19+57\)

\(\Rightarrow3,8\times y=76\)

\(\Rightarrow y=76:3,8\)

\(\Rightarrow y=20\)