=-3/31-6/17+1/25-28/31-11/17-1/5

=-1-1-4/25=-2-4/25=-54/25

b: D=(-3/31-28/31)+(-6/17-11/17)+(1/25-5/25)

=-2-4/25=-54/25

=\(-\dfrac{54}{25}\)

\(=\left[\left(-\dfrac{3}{31}\right)+\left(-\dfrac{28}{31}\right)\right]+\left[\left(-\dfrac{6}{17}\right)+\left(-\dfrac{11}{17}\right)\right]+\left[\dfrac{1}{25}+\left(-\dfrac{1}{5}\right)\right]\)

\(=\left(-1\right)+\left(-1\right)+\left[\dfrac{1}{25}+\left(-\dfrac{5}{25}\right)\right]\)

\(=\left(-1\right)+\left(-1\right)+\left(-\dfrac{4}{25}\right)\)

\(=\left(-2\right)+\left(-\dfrac{4}{25}\right)\)

\(=\left(-\dfrac{50}{25}\right)+\left(-\dfrac{4}{25}\right)\)

\(=-\dfrac{54}{25}\)

\(=\left(\dfrac{-3}{31}+\dfrac{-28}{31}\right)+\left(\dfrac{-6}{17}+\dfrac{-11}{17}\right)+\left(\dfrac{1}{25}+\dfrac{1}{5}\right)\)

\(=-1+-1+\left(\dfrac{1}{25}+\dfrac{-5}{25}\right)\)

\(=-2\)\(+\dfrac{-4}{25}\)

\(=\)\(\dfrac{50}{25}+\dfrac{-4}{25}\)

=\(\dfrac{46}{25}\)

A = - \(\dfrac{3}{31}\)  - \(\dfrac{6}{17}\) + \(\dfrac{1}{2}\) - \(\dfrac{28}{31}\) - \(\dfrac{11}{17}\)- \(\dfrac{1}{6}\)

A = -( \(\dfrac{3}{31}\) + \(\dfrac{28}{31}\)) - ( \(\dfrac{6}{17}\) + \(\dfrac{11}{17}\)) +( \(\dfrac{1}{2}\)- \(\dfrac{1}{6}\))

A = - \(\dfrac{31}{31}\) - \(\dfrac{17}{17}\)+ \(\dfrac{1}{3}\)

A = -1 - 1 + \(\dfrac{1}{3}\)

A = \(-\dfrac{5}{3}\)

Mik cần nhanh, mai mik hok r T^T

1) Tính nhanh 

\(A=\frac{4}{7}+\frac{3}{4}+\frac{2}{7}+\frac{5}{4}+\frac{1}{7}\)

\(=\left(\frac{4}{7}+\frac{2}{7}+\frac{1}{7}\right)+\left(\frac{3}{4}+\frac{5}{4}\right)\)

\(=1+2=3\)

Ghép tương tự vs B 

A = \(\frac{4}{7}+\frac{3}{4}+\frac{2}{7}+\frac{5}{4}+\frac{1}{7}\)

   = \(\left(\frac{2}{7}+\frac{4}{7}+\frac{1}{7}\right)+\left(\frac{3}{4}+\frac{5}{4}\right)\)

   =           \(1+2\)

   =            \(3\)

âm 2( số -2) và 4/25

\(\frac{-3}{31}+\frac{-6}{17}+\frac{1}{25}+\frac{-28}{31}+\frac{-11}{17}+\frac{-1}{5}\)

\(=\left(\frac{-3}{31}+\frac{-28}{31}\right)+\left(\frac{-6}{17}+\frac{-11}{17}\right)+\left(\frac{1}{25}+\frac{-1}{5}\right)\)

\(=\frac{-31}{31}+\frac{-17}{17}+\frac{-4}{25}\)

\(=\left(-1\right)+\left(-1\right)+\frac{-4}{25}\)

\(=\frac{\left(-25\right)+\left(-25\right)+\left(-4\right)}{25}\)

\(=\frac{-54}{25}\)

(-3/31+-28/31)+(6/17+11/17)+1/25+-1/5

-1+-1+1/25 +-1/5

-2+1/25+-1/5

-2/1+1/25+-1/5

-50/25+1/25+-5/25

-49/25+-5/25

-54/25

mik đúng mn k  cho mik nha cảm ơn mn

a: =-5/9-4/9+8/15+7/15-2/11=-2/11

b: =10/17+7/17-5/13-8/13+11/25

=11/25

c: =(9/12-2/12)*3/2=7/12*3/2=21/24=7/8

d: =(31/10-25/10)*3-2

=3/5*3-2

=9/5-2

=-1/5