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a: TH1: \(\left(\frac67+\frac{a}{b}\right)=3\times\left(\frac29+\frac{a}{b}\right)\)
=>\(\frac23+3\times\frac{a}{b}=\frac{a}{b}+\frac67\)
=>\(2\times\frac{a}{b}=\frac67-\frac23=\frac{18-14}{21}=\frac{4}{21}\)
=>\(\frac{a}{b}=\frac{2}{21}\)
TH2: \(\left(\frac67+\frac{a}{b}\right)=\frac13\times\left(\frac29+\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac67=\frac{2}{27}+\frac13\times\frac{a}{b}\)
=>\(\frac23\times\frac{a}{b}=\frac{2}{27}-\frac67=\frac{14-162}{189}=\frac{-148}{189}\)
=>\(\frac{a}{b}=\frac{-148}{189}:\frac23=\frac{-148}{189}\times\frac32=\frac{-74}{63}\) (loại)
b: TH1: \(\frac{a}{b}+\frac19=3\times\left(\frac67-\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac19=\frac{18}{7}-3\times\frac{a}{b}\)
=>\(4\times\frac{a}{b}=\frac{18}{7}-\frac19=\frac{162-7}{63}=\frac{155}{63}\)
=>\(\frac{a}{b}=\frac{155}{63}:4=\frac{155}{252}\)
TH2: \(\frac{a}{b}+\frac19=\frac13\times\left(\frac67-\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac19=\frac27-\frac13\times\frac{a}{b}\)
=>\(\frac43\times\frac{a}{b}=\frac27-\frac19=\frac{18-7}{63}=\frac{11}{63}\)
=>\(\frac{a}{b}=\frac{11}{63}:\frac43=\frac{11}{63}\times\frac34=\frac{11}{21\times4}=\frac{11}{84}\)
bài 1 :
=> hiệu hai số là :
9 x 2 + 1 =19
=>số lớn là:
(2011+19):2=1015
=>số bé là:
2011-1015=996
đ/s...
a: TH1: \(\left(\frac67+\frac{a}{b}\right)=3\times\left(\frac29+\frac{a}{b}\right)\)
=>\(\frac23+3\times\frac{a}{b}=\frac{a}{b}+\frac67\)
=>\(2\times\frac{a}{b}=\frac67-\frac23=\frac{18-14}{21}=\frac{4}{21}\)
=>\(\frac{a}{b}=\frac{2}{21}\)
TH2: \(\left(\frac67+\frac{a}{b}\right)=\frac13\times\left(\frac29+\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac67=\frac{2}{27}+\frac13\times\frac{a}{b}\)
=>\(\frac23\times\frac{a}{b}=\frac{2}{27}-\frac67=\frac{14-162}{189}=\frac{-148}{189}\)
=>\(\frac{a}{b}=\frac{-148}{189}:\frac23=\frac{-148}{189}\times\frac32=\frac{-74}{63}\) (loại)
b: TH1: \(\frac{a}{b}+\frac19=3\times\left(\frac67-\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac19=\frac{18}{7}-3\times\frac{a}{b}\)
=>\(4\times\frac{a}{b}=\frac{18}{7}-\frac19=\frac{162-7}{63}=\frac{155}{63}\)
=>\(\frac{a}{b}=\frac{155}{63}:4=\frac{155}{252}\)
TH2: \(\frac{a}{b}+\frac19=\frac13\times\left(\frac67-\frac{a}{b}\right)\)
=>\(\frac{a}{b}+\frac19=\frac27-\frac13\times\frac{a}{b}\)
=>\(\frac43\times\frac{a}{b}=\frac27-\frac19=\frac{18-7}{63}=\frac{11}{63}\)
=>\(\frac{a}{b}=\frac{11}{63}:\frac43=\frac{11}{63}\times\frac34=\frac{11}{21\times4}=\frac{11}{84}\)