Giúp mk nha

-3/7

CHÚC ANH/ CHỊ HỌC GIỎI

Bài 2. > , < ,  = ?

5/7 < 4/3             2/5 < 6/10            1/4 = 3/12                27/36 >

2/9           7/6 > 7/9

7/2 = 2/7        15/23 < 1                  27/9 > 2          14/15 < 1          51/17 < 4

tính máy tính là ra ấy mà !!! Kết quả là -3/7

\(\frac{1}{3}\cdot\frac{5}{7}-\frac{7}{27}\cdot\frac{36}{14}\)

=\(\frac{5}{21}\cdot\frac{2}{3}\)

=\(\frac{10}{63}\)

\(27\cdot36+73\cdot99+27\cdot14-49\cdot7\)

\(=27\cdot\left(36+14\right)+73\cdot99-49\cdot7\)

\(=27\cdot50+6884=1350+6884=8234\)

\(\dfrac{5^6}{5^4}+2^3\cdot2^2-1^{2017}\)

\(=5^2+2^5-1\)

=25+32-1

=25+31

=56

a, 1/2 x ( 2/9 + 3/7 - 5/27 )

= 1/2 x ( 41/63 - 5/27 )

= 1/2 x 88/189

= 44/189

b, (-5/8 + 1,75 + 8/35) : (-3 và 9/10)

= (-5/8 + 7/4 + 8/35) : (-39/10)

= (9/8 + 8/35) : (-39/10)

=379/280 : (-39/10)

= -379/1092

c, 1/3 x 5/7 - 5/27 x 36/14

= 5/21 - 10/21

= -5/21

Chúc bạn học tốt !

a) 1/2 x  (\(\frac{42}{189}-\frac{81}{189}-\frac{35}{189}\))=1/2 x 88/189 = 44/189

b) ( \(\frac{-5}{8}+\frac{7}{4}+\frac{8}{35}\)) : \(-3\frac{9}{10}\)

= ( \(\frac{-175}{280}+\frac{490}{280}+\frac{64}{280}\)) : \(\frac{-39}{10}\)

=\(\frac{379}{280}\)  x \(\frac{-10}{39}\)=\(\frac{-379}{1092}\)

c) \(\frac{5}{21}\)- \(\frac{10}{21}\)= \(\frac{-5}{21}\)

\(\frac{1}{3}\times\frac{5}{7}-\frac{7}{27}\times\frac{36}{14}\)\(=\frac{1\times5}{3\times7}-\frac{7\times36}{27\times14}\)\(=\frac{5}{21}-\frac{252}{378}=\frac{5}{21}-\frac{2}{3}=\frac{5}{21}-\frac{14}{21}\)\(=\frac{5-14}{21}=\frac{-9}{21}=\frac{-3}{7}\)

\(\frac{1}{3}.\frac{5}{7}-\frac{7}{27}.\frac{36}{14}=\frac{5}{21}-\frac{2}{3}=-\frac{9}{21}=-\frac{3}{7}\)

Bài 1:

a; \(\dfrac{5}{18}\) + \(\dfrac{8}{19}\) - \(\dfrac{7}{21}\) + (- \(\dfrac{10}{36}\) + \(\dfrac{11}{19}\)  + \(\dfrac{1}{3}\)) - \(\dfrac{5}{8}\)

=  \(\dfrac{5}{18}\) + \(\dfrac{8}{19}\) - \(\dfrac{1}{3}\) -\(\dfrac{10}{36}\) + \(\dfrac{11}{19}\) + \(\dfrac{1}{3}\) - \(\dfrac{5}{8}\)

= (\(\dfrac{5}{18}\) - \(\dfrac{10}{36}\)) + (\(\dfrac{8}{19}\) + \(\dfrac{11}{19}\)) - (\(\dfrac{1}{3}\) - \(\dfrac{1}{3}\)) - \(\dfrac{5}{8}\)

= (\(\dfrac{5}{18}\) - \(\dfrac{5}{18}\)) + \(\dfrac{19}{19}\) - 0 - \(\dfrac{5}{8}\)

= 0 + 1 - \(\dfrac{5}{8}\)

= \(\dfrac{3}{8}\)

b; \(\dfrac{1}{13}\) + (\(\dfrac{-5}{18}\) - \(\dfrac{1}{13}\) + \(\dfrac{12}{17}\)) - (\(\dfrac{12}{17}\) - \(\dfrac{5}{18}\) + \(\dfrac{7}{5}\))

= \(\dfrac{1}{13}\) - \(\dfrac{5}{18}\) - \(\dfrac{1}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{12}{17}\) + \(\dfrac{5}{18}\) - \(\dfrac{7}{5}\)

= (\(\dfrac{1}{13}\) - \(\dfrac{1}{13}\)) + (\(\dfrac{12}{17}\) - \(\dfrac{12}{17}\)) + (-\(\dfrac{5}{18}\) + \(\dfrac{5}{18}\)) - \(\dfrac{7}{5}\)

= 0 + 0 + 0 - \(\dfrac{7}{5}\)

= - \(\dfrac{7}{5}\)

Bài 1 c;

   \(\dfrac{15}{14}\) - (\(\dfrac{17}{23}\) - \(\dfrac{80}{87}\) + \(\dfrac{5}{4}\)) + (\(\dfrac{17}{23}\) - \(\dfrac{15}{14}\) + \(\dfrac{1}{4}\))

=  \(\dfrac{15}{14}\) - \(\dfrac{17}{23}\) + \(\dfrac{80}{87}\) - \(\dfrac{5}{4}\) + \(\dfrac{17}{23}\) - \(\dfrac{15}{14}\) + \(\dfrac{1}{4}\)

= (\(\dfrac{15}{14}-\dfrac{15}{14}\)) + (\(-\dfrac{17}{23}+\dfrac{17}{23}\)) - (\(\dfrac{5}{4}\) - \(\dfrac{1}{4}\)) + \(\dfrac{80}{87}\)

= 0 + 0 - 1 + \(\dfrac{80}{87}\)

= - \(\dfrac{7}{87}\)

1/3.5/7-7/27.36/14

=1/3.5/7-7/27.18/7

=5/21-2/3

=5/21-14/21

=-9/21=-3/7

****

1/3.5/7-7/27.36/14

=1/3.5/7-7/27.18/7

=5/21-2/3

=5/21-14/21

=-9/21=-3/7