(2^31-31^2).(.........).(...........).(2^4-4^2)

=.............................................x (16-16)

=..............................................x 0

=0

Lời giải:
a. $=5.9+112-31=45+112-31=157-31=126$

b. $=-31-82-17=-(31+82+17)=-130$

c. $=6.(-8)+20+12=-48+32=-(48-32)=-16$

d. Trùng với câu b.

sory câu hỏi bị sai rồi

\(\frac{2}{5}.\frac{19}{31}+\frac{2}{5}.\frac{43}{31}-2017\frac{4}{5}\)

\(=\frac{2}{5}.\left(\frac{19}{31}+\frac{43}{31}\right)-\frac{10089}{5}\)

\(=\frac{2}{5}.2-\frac{10089}{5}\)

\(=\frac{4}{5}-\frac{10089}{5}\)

\(=\frac{-10085}{5}\)

\(=-2017\)

CHÚC BẠN HỌC TỐT !!!!!!!!!!!!!! 

\(\frac{2}{5}.\frac{19}{31}+\frac{2}{5}.\frac{43}{31}-2017\frac{4}{5}\)

\(=\frac{2}{5}\left(\frac{19}{31}+\frac{43}{31}\right)-\frac{10089}{5}\)

\(=\frac{2}{5}.2-\frac{10089}{5}\)

\(=\frac{4}{5}-\frac{10089}{5}=-2017\)

=7/30

4/3 + -11/31 + 3/10 - 20/31 - 2/5 = 7/30

og có thể giải ra dc ko

C

C

C NHA BẠN 

CHÚC BẠN HỌC TỐT ^^

2/135

=2/135

chuc hoc tot

minh xin loi 

31.15.7².4-31.49.40

=31.15.49.4-31.49.40

=31.49(15.4-40)

=31.49.20

=30380

#)Giải :

\(200-18:\left(372:3x-1\right)-28=166\)

\(\Leftrightarrow200-18:\left(372:3x-1\right)=194\)

\(\Leftrightarrow18:\left(372:3x-1\right)=6\)

\(\Leftrightarrow372:3x-1=3\)

\(\Leftrightarrow3x-1=124\)

\(\Leftrightarrow3x=125\)

\(\Leftrightarrow x=\frac{125}{3}\)

200 - 18 : (372 : 3 . x - 1) - 28 = 166

=> 200 - 18 : (372 : 3.x - 1)     = 166 + 28

=> 200 - 18 : (372 : 3.x) - 1)    = 194

=>          18 : (372 : 3.x - 1)     = 200 - 194

=>          18 : (372 : 3.x - 1)     = 6

=>                  372 : 3.x  - 1      = 18 : 6

=>                  372 : 3.x - 1       = 3

=>                    372 : 3.x          = 3 + 1

=>                    372 : 3.x          = 4

=>                             3.x          = 372 : 4

=>                             3.x          = 93

=>                                x          = 93 : 3

=>                                x          = 31

#)Next:

\(\left(100-99+98-97+...+2-1\right):50+2010-12x=91\)

\(\Leftrightarrow\left[\left(100-99\right)+\left(98-97\right)+...+\left(2-1\right)\right]:50+2010-12x=91\)

\(\Leftrightarrow\left[1+1+...+1\right]:50+2010-12x=91\)

\(\Leftrightarrow50:50+2010-12x=91\)

\(\Leftrightarrow1+2010-12x=91\)

\(\Leftrightarrow2011-12x=91\)

\(\Leftrightarrow12x=1920\)

\(\Leftrightarrow x=160\)

\(\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}\)

\(=\dfrac{4}{3}+\left(\dfrac{-11}{31}+\dfrac{-20}{31}\right)+\left(\dfrac{3}{10}-\dfrac{2}{5}\right)\)

\(=\dfrac{4}{3}+-1+\dfrac{-1}{10}\)

\(=\dfrac{1}{3}+\dfrac{-1}{10}\)

\(=\dfrac{7}{30}\)

Chúc bạn học tốt

= 91/93 + -107/310 - 2/5

= 19/30 - 2/5

= 7/30

= 4/3 -11/31 +  3/10 - 20/31 - 2/5

= 4/3 +3/10 - 2/5 +(-11/31 - 20/31)

= 37/30 -1 = 7/30