a)CR= \(\frac{1}{5}\):2 =\(\frac{1}{10}\)(m) DT = \(\frac{1}{10}\) . \(\frac{1}{4}\) =\(\frac{1}{40}\)(m) b) Cat doc

A = {x / x = 1 + 6y; y \(\in\)N; 0 \(\le\)y \(\le\)6 }