[tex]a)\\\\3.5:7-0.004*40=\frac{35}{70}-0.16=\frac{50}{100}-\frac{16}{100}=\frac{34}{100}=0.34[/tex]
[tex]b)\\\\0.1^2:0.04^2=(\frac{0.1}{0.04})^2=(\frac{1}{10}:\frac{4}{100})^2=(\frac{1}{10}*\frac{100}{4})^2=(\frac{10}4)^2=\frac{100}{16}=\frac{25}4=6.25[/tex]
[tex]c)\\\\2.6-0.6*0.05=\frac{26}{10}-\frac{6}{10}*\frac{5}{100}=\frac{26}{10}-\frac32*\frac{1}{50}=\frac{26}{10}-\frac{3}{100}=\frac{260}{100}-\frac{3}{100}=\frac{257}{100}=2.57[/tex]