Gọi số hộp bánh Danisa, Kitkat, yến mạch lần lượt là x,y,z (x,y,z ϵ N*)

Theo đề bài ta có: 140x = 80y = 40z biết z - y = 7

Vậy nên:

\(\dfrac{x}{\dfrac{1}{140}}\) = \(\dfrac{y}{\dfrac{1}{80}}\) = \(\dfrac{z}{\dfrac{1}{40}}\) = \(\dfrac{z-y}{\dfrac{1}{40}-\dfrac{1}{80}}\) = \(\dfrac{7}{\dfrac{1}{80}}\)

=>x= \(\dfrac{1}{140}\) .7.80 = 4

Vậy mẹ đã mua \(4\) hộp bánh Danisa.

\(\left(1,41423\right)^3\) : x = \(\left(1,41423\right)^2\)

                    x =\(\left(1,41423\right)^3\) : \(\left(1,41423\right)^2\)

                    x =\(1,41423\)

a) 0,2 + 1\(\dfrac{3}{7}\) - \(\dfrac{6}{5}\)

=\(\dfrac{5}{10}\) + \(\dfrac{10}{7}\) +\(\dfrac{6}{5}\)

=(\(\dfrac{5}{10}\) + \(\dfrac{6}{5}\)) +\(\dfrac{10}{7}\)

=(\(\dfrac{5}{10}\) + \(\dfrac{12}{10}\)) + \(\dfrac{10}{7}\)

=\(\dfrac{17}{10}\) + \(\dfrac{10}{7}\)

=\(\dfrac{219}{70}\)

b) (\(\dfrac{4}{5}\) - 1) : \(\dfrac{3}{5}\) - \(\dfrac{2}{3}\).0,5

=\(\dfrac{-1}{5}\) :  \(\dfrac{3}{5}\) - \(\dfrac{2}{3}\).0,5

=\(\dfrac{-1}{3}\) - \(\dfrac{1}{3}\)

=\(\dfrac{-2}{3}\)

 m

\(^{_{ }\max\limits_{ }}\)

a) 5/2/2023