1,\(\left(\frac{7}{2}-2x\right).\frac{4}{3}=\frac{22}{3}\)

\(x.\left(\frac{7}{2}-2\right)=\frac{22}{3}:\frac{4}{3}=\frac{22}{3}.\frac{3}{4}=\frac{11}{2}\)

\(x.\frac{3}{2}=\frac{11}{2}\)

\(x=\frac{11}{2}:\frac{3}{2}=\frac{11}{2}.\frac{2}{3}=\frac{11}{3}\)

Câu a:

\(\frac{x+5}{x+9}\) = \(\frac{x+4}{x+3}\)

(\(x\) + 5)(\(x+3\)) = (\(x+4\))(\(x+9\))

\(x^2\) + 3\(x\) + 5\(x\) + 15 = \(x^2\) + 9\(x\) + 4\(x\) + 36

\(x^2+3x+5x\) - \(x^2-9x\) - 4\(x\) = 36 - 15

(\(x^2-x^2\)) + (\(3x+5x\) - 9\(x-4x\)) = 21

0 + (8\(x\) - 9\(x\) - 4\(x\)) = 21

-\(x-4x\) = 21

-5\(x\) = 21

\(x\) = 21 : (-5)

\(x\) = - \(\frac{21}{5}\)

Vậy \(x=-\frac{21}{5}\)

a) \(\frac{2}{3}\left(\frac{1}{2}+\frac{3}{4}-\frac{1}{3}\right)\le\frac{x}{18}\)

\(\frac{x}{18}\le\frac{7}{3}\left(\frac{1}{2}-\frac{1}{6}\right)\)

tu tim x o 2 truong hop tren
b) de \(\frac{11}{2x+1}\) nguyen thi \(2x+1\inƯ\left(11\right)=\left\{\pm1;\pm11\right\}\)

2x+1=-1 suy ra x=-1

2x+1=1 suy ra x=0

2x+1=11 suy ra x=5

2x+1=-11 suy ra x=-6

Vay de ......thi x thuoc {-1;0;5;6}

cảm ơn bạn

e, \(18x-19=21+8x\)

\(\Rightarrow18x-8x=21+19\)

\(\Rightarrow10x=30\)

\(\Rightarrow x=3\)

Vậy \(x=3\)

g, \(18-4x=-20-6x\)

\(\Rightarrow-4x+6x=-20-18\)

\(\Rightarrow-2x=-38\)

\(\Rightarrow x=19\)

Vậy \(x=19\)

h, \(-15x-24=-7x-32\)

\(\Rightarrow-15x+7x=-32+24\)

\(\Rightarrow-8x=-8\)

\(\Rightarrow x=1\)

Vậy \(x=1\)

i, \(15x-3\left(4x-6\right)=-12+36\)

\(\Rightarrow15x-12x+18=-12+36\)

\(\Rightarrow7x=-12+36-18\)

\(\Rightarrow7x=6\)

\(\Rightarrow x=\frac{6}{7}\)

Vậy \(x=\frac{6}{7}\)

k, \(-10x-27=-7x+33\)

\(\Rightarrow-10x+7x=33+27\)

\(\Rightarrow-3x=60\)

\(\Rightarrow x=-20\)

m, \(-17x-24=-9x-40\)

\(\Rightarrow-17x+9x=-40+24\)

\(\Rightarrow-8x=-16\)

\(\Rightarrow x=2\)

Vậy \(x=2\)

n, \(-23x-25=-18x+75\)

\(\Rightarrow-23x+18x=75+25\)

\(\Rightarrow-5x=100\)

\(\Rightarrow x=-20\)

Vậy \(x=-20\)

p, \(-5x+7\left(2x-3\right)=4\left(x-4\right)\)

\(\Rightarrow-5x+14x-21=4x-16\)

\(\Rightarrow-5x+14x-4x=-16+21\)

\(\Rightarrow5x=5\)

\(\Rightarrow x=1\)

Vậy \(x=1\)

q, \(24-6\left(3x+1\right)=-5\left(4x-4\right)-8\)

\(\Rightarrow24-18x-6=-20x+20-8\)

\(\Rightarrow-18x+20x=20-8-24+6\)

\(\Rightarrow2x=-6\)

\(\Rightarrow x=-3\)

Vậy \(x=-3\)

r, \(18-4\left(6-2x\right)=-3\left(4x+5\right)-11\)

\(\Rightarrow18-24+8x=-12x-15-11\)

\(\Rightarrow8x+12x=-15-11-18+24\)

\(\Rightarrow20x=-20\)

\(\Rightarrow x=-1\)

Vậy \(x=-1\)

s, \(-5\left(4x-5\right)-14=6\left(2-3x\right)-10x-9\)

\(\Rightarrow-20x+25-14=12-18x-10x-9\)

\(\Rightarrow-20x+18x+10x=12-9+14-25\)

\(\Rightarrow8x=-8\)

\(\Rightarrow x=-1\)

Vậy \(x=-1\)

Chúc bạn hok tốt!!! tỷ tỷ

b) \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{499}{1000}\)

\(\dfrac{2}{6}+\dfrac{2}{12}+\dfrac{2}{20}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{499}{1000}\)

\(\dfrac{2}{2.3}+\dfrac{2}{3.4}+\dfrac{2}{4.5}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{499}{1000}\)

mik lỡ bấm nhầm rồi, phần sau bn tự nghĩ nhé, sorry

khó quá 

\(a.\frac{-5}{9}+\frac{5}{9}:A=\left(-\frac{5}{9}+\frac{5}{9}\right):A=0:A=0\)

\(b.\frac{7}{25}.\frac{11}{13}-\frac{7}{25}.\frac{2}{13}-\frac{8}{25}=\frac{7}{25}.\left(\frac{11}{13}-\frac{2}{13}\right)-\frac{8}{25}=\frac{7}{25}.\frac{9}{13}-\frac{8}{25}=\frac{63}{325}-\frac{8}{25}=\frac{-41}{325}\)

C.Thua

Đúng 100%

Đúng 100%

Đúng 100%

Dấu " / " là phân số nhé

a) 5/-4 . 16/25 + -5/4 . 9/25

= -5/4 . 16/25 + -5/4 . 9/25

= -5/4 . ( 16/25 + 9/25 )

= -5/4 . 1

= -5/4

b) 4 11/23 - 9/14 + 2 12/23 - 5/4

= 103/23 - 9/14 + 58/23 - 5/4

= 103/23 + 58/23 - 9/14 - 5/4

= 7 - 9/14 - 5/4

= 143/28

c) 2 13/27 - 7/15 + 3 14/27 - 8/15

= 67/27 - 7/15 + 95/27 - 8/15

= 67/27 + 95/27 - 7/15 - 8/15

= 6 - 7/15 - 8/15

= 5

k) \(2x-49=5.3^2\)

\(2x-49=45\)

\(2x=49+45\)

\(2x=94\)

\(x=47\)

l) \(3^2.\left(x+14\right)-5^2=5.2^2\)

\(9.\left(x+14\right)-25=20\)

\(9.\left(x+14\right)=45\)

\(x+14=5\)

\(x=-9\)

m) \(6x+x=5^{11}:5^9+3^1\)

\(7x=5^{11-9}+3\)

\(7x=5^2+3\)

\(7x=28\)

\(x=4\)

n) \(7x-x=5^{21}:5^{19}+3.2^2-\left(-7^{-0}\right)\)

\(6x=5^{21-19}+12-1\)

\(6x=5^2+11\)

\(6x=36\)

\(x=6\)

o) \(7x-2x=6^{17}:6^{15}+44:11\)

\(5x=6^{17-15}+4\)

\(5x=6^2+4\)

\(5x=40\)

\(x=8\)

o)7x-x=5²¹:5¹⁹+3.2²-7⁰

=> 6x = 5^2 + 12 -1

=> 6x = 36

=> x = 36/6 = 6

Kết quả 6

Học tốt

\(a)\frac{-3}{4}+\frac{3}{7}+-\frac{1}{4}+\frac{4}{9}+\frac{4}{7}\)

\(=\left(\frac{-3}{4}+-\frac{1}{4}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)+\frac{4}{9}\)

\(=-1+1+\frac{4}{9}\)

\(=\frac{4}{9}\)

\(\frac{-3}{4}+\frac{3}{7}+\frac{-1}{4}+\frac{4}{9}+\frac{4}{7}\)

\(=\left(\frac{-3}{4}+\frac{-1}{4}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)+\frac{4}{9}\)

\(=\left(-1\right)+1+\frac{4}{9}\)

\(=0+\frac{4}{9}\)

\(=\frac{4}{9}\)