Câu 1 :
a) \(12:\frac{3}{4}-1\frac{1}{5}\times5\) b) \(2,24:0,2+2,5:0,5-1,68\)
\(=12:\frac{3}{4}-\frac{7}{5}\times5\) \(=11,2+5-1,68\)
\(=16-7\) \(=11,7-1,68\)
\(=9\) \(=10,02\)
Câu 2 :
a) \(\frac{5}{2}\times x-\frac{3}{2}=\frac{3}{2}:\frac{1}{4}\) b) \(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{6}\right)+\left(x+\frac{1}{12}\right)+\left(x+\frac{1}{20}\right)=2\)
\(\frac{5}{2}\times x-\frac{3}{2}=6\) \(\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\right)=2\)
\(\frac{5}{2}\times x=6+\frac{3}{2}\) \(x\times4+\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\right)=2\)
\(\frac{5}{2}\times x=\frac{15}{2}\) \(x\times4+\left(\frac{2}{3}+\frac{1}{12}+\frac{1}{20}\right)=2\)
\(x=\frac{15}{2}:\frac{5}{2}\) \(x\times4+\left(\frac{3}{4}+\frac{1}{20}\right)=2\)
\(x=3\) \(x\times4+\frac{4}{5}=2\)
\(x\times4=2-\frac{4}{5}\)
\(x\times4=\frac{6}{5}\)
\(x=\frac{6}{5}:4\)
\(x=\frac{3}{10}\)
Chúc bạn hok tốt !