(-3/4+2/3):5/11+(-1/4+1/3):5/11

a)|x-13|-35-45=-47

b)(4+x).(x+3)=0

c)25-(5-x)=120-(28-5)

a: =5,3-0,7-5,3=-0,7

b: =5,3-10+3,1+4,7

=10-10+3,1=3,1

c: =9+3,6-4,1+1,3

=9+0,8=9,8

d: =21/47+26/47+1/5+4/5

=1+1

=2

e: =3/8(58/3-33/3)

=3/8*25/3

=25/8

Bài 1:

a) \(\left(\frac{9}{25}-2.18\right):\left(3\frac{4}{5}+0,2\right)\)

\(=\left(\frac{9}{25}-36\right):\left(\frac{19}{5}+\frac{1}{5}\right)\)

\(=\left(\frac{9}{25}-\frac{900}{25}\right):4\)

\(=-\frac{891}{25}.\frac{1}{4}\)

\(=-\frac{891}{100}\)

b) \(\frac{3}{8}.19\frac{1}{3}-\frac{3}{8}.33\frac{1}{3}\)

\(=\frac{3}{8}.\frac{58}{3}-\frac{3}{8}.\frac{100}{3}\)

\(=\frac{3}{8}\left(\frac{58}{3}-\frac{100}{3}\right)\)

\(=\frac{3}{8}\left(-\frac{42}{3}\right)\)

\(=\frac{3}{8}.\left(-14\right)\)

\(=-\frac{21}{4}\)

c) \(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

\(=\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{1}{2}+\frac{16}{21}\)

\(=\frac{27}{23}+\frac{5}{21}+\left(-\frac{4}{23}\right)+\frac{1}{2}+\frac{16}{21}\)

\(=\left[\frac{27}{23}+\left(-\frac{4}{23}\right)\right]+\left(\frac{5}{21}+\frac{16}{21}\right)+\frac{1}{2}\)

\(=1+1=2\)

d) \(\frac{21}{47}+\frac{9}{45}+\frac{26}{47}+\frac{4}{5}\)

\(=\frac{21}{47}+\frac{9}{45}+\frac{26}{47}+\frac{36}{45}\)

\(=\left(\frac{21}{47}+\frac{26}{47}\right)+\left(\frac{9}{45}+\frac{36}{45}\right)\)

\(=1+1=2\)

Mình chỉ cho đáp án thôi,sai thì châm chước cho mìn nha!

a)-91 phần200

b)-25phần 4

c)5 phần 2

d)2

e)0

a, ( 0,36-2,18) : ( 3,8 + 0,2)

= -1,82 : 4

=-0,455 hay -91/200

b, 3/8*19/1/3-3/8*33/1/3

=3/8*(19/1/3-33/1/3)

=3/8*(-14)

=-21/4

Bài 2: 

a: =>x-35=-23

=>x=12

b: =>|x-8|=13

=>x-8=13 hoặc x-8=-13

=>x=21 hoặc x=-5

Bài 1: 

a: =42-98-42+12-12=-98

b: =10x4x3x(-25)=40x(-25)x3=-1000x3=-3000

1: \(=15\cdot\dfrac{4}{9}-\dfrac{7}{3}=\dfrac{20}{3}-\dfrac{7}{3}=\dfrac{13}{3}\)

2: \(=\left(\dfrac{9}{25}-36\right):\left(\dfrac{19}{5}+\dfrac{1}{5}\right)\)

\(=\left(\dfrac{9}{25}-\dfrac{900}{25}\right):4\)

\(=\dfrac{-891}{100}\)

3: \(=\dfrac{3}{8}\left(\dfrac{58}{3}-\dfrac{100}{3}\right)=\dfrac{3}{8}\cdot\left(-14\right)=-\dfrac{42}{8}=-\dfrac{21}{4}\)

\(\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{4}{5}\)

\(=\left(\dfrac{21}{47}+\dfrac{26}{47}\right)+\left(\dfrac{9}{45}+\dfrac{4}{5}\right)\)

\(=1+1\)

\(=2\)

a)\(\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{9}{45}\\ =\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{1}{5}\\ =\dfrac{14-15+1}{35}\\ =\dfrac{0}{35}=0\)

b)\(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}\\ =\left(\dfrac{1}{3}-\dfrac{4}{3}\right)+\left(\dfrac{14}{25}+\dfrac{11}{25}\right)+\dfrac{2}{7}\\ =-1+1+\dfrac{2}{7}\\ =0+\dfrac{2}{7}=\dfrac{2}{7}\)

A = 2/1*5 + 2/5*9 + ... + 2/101*105

   = 1/2(4/1*5 + 4/5*9 + ... + 4/101*105)

   = 1/2(1 - 1/5 + 1/5 - 1/9 + ... + 1/101 - 1/105)

   = 1/2(1 - 1/105)

   = 1/2 * 104/105 = 52/105

Sửa câu b. Phân số thứ 2 phải là 4/5*8

B = 4/2*5 + 4/5*8 + ... + 4/47*50

   = 4/3(3/2*5 + 3/5*8 + ... + 3/47*50)

   = 4/3(1/2 - 1/5 + 1/5 - 1/8 + ... + 1/47 - 1/50)

   = 4/3(1/2 - 1/50)

   = 4/3 * 24/50 = 16/25