\(\overline{0,a}\times\overline{0,b}\times\overline{a,b}=\overline{0,bbb}\)
\(=\left(a\times0,1\right)\times\left(b\times0,1\right)\times\left(\overline{ab}\times0,1\right)=\overline{bbb}\div1000\)
\(=a\times b\times\overline{ab}\times0,1\times0,1\times0,1=\overline{bbb}\div1000\)
\(=a\times b\times\overline{ab}\times0,001=\overline{bbb}\div1000\)
\(=a\times b\times\overline{ab}\div1000=\overline{bbb}\div1000\)
\(\Rightarrow a\times b\times\overline{ab}=\overline{bbb}\)
\(=a\times b\times\overline{ab}=b\times111\)
\(\Rightarrow a\times\overline{ab}=111\)
\(\Rightarrow a=3\)
\(\Rightarrow3\times\overline{3b}=111\)
\(\Rightarrow\overline{3b}=37\)
\(\Rightarrow b=7\)
Thay số:
\(0,3\times0,7\times3,7=0,777\)
3)13,ab:2,6=a,b
\(\Rightarrow\)a,b*2,6=13,ab
a,b*2,6*100=13,ab*100
a,b*10*2,6*10=13ab
ab*26=13ab
ab*26=1300+ab
ab*26-ab=1300
ab*(26-1)=1300
ab*25=1300
ab=1300:25
ab=52
Vậy a=5;b=2