\(\frac{x-20}{7}+\frac{x-46}{33}+\frac{x-5}{8}+\frac{x+6}{19}=0\)

\(\Leftrightarrow\)\(\left(\frac{x-20}{7}+1\right)+\left(\frac{x-46}{33}+1\right)+\left(\frac{x-5}{8}-1\right)+\left(\frac{x+6}{19}-1\right)=0\)

\(\Leftrightarrow\)\(\frac{x-13}{7}+\frac{x-13}{33}+\frac{x-13}{8}+\frac{x-13}{19}=0\)

\(\Leftrightarrow\)\(\left(x-13\right)\left(\frac{1}{7}+\frac{1}{33}+\frac{1}{8}+\frac{1}{19}\right)=0\)

\(\Leftrightarrow\)\(x-13=0\)       (vi  1/7 + 1/33 + 1/8 + 1/19 \(\ne0\))

\(\Leftrightarrow\)\(x=13\)

Vậy phương trình có nghiệm là     \(x=13\)

pt <=> ( x-20/7 +1 ) + ( x-46/33 + 1 ) + ( x-5/8 - 1 ) + ( x+6/19 - 1 ) = 0

<=> x-13/7 + x-13/33 + x-13/8 + x-13/19 = 0

<=> (x-13).( 1/7+1/33+1/8+1/19 ) = 0

<=> x-13 = 0 ( vì 1/7+1/33+1/8+1/19 > 0 )

<=> x=13

Vậy x=13

Tk mk nha

\(\frac{x-20}{7}+\frac{x-46}{33}+\frac{x-5}{8}+\frac{x+6}{19}=0\)

\(\Leftrightarrow\left(\frac{x-20}{7}+1\right)+\left(\frac{x-46}{33}+1\right)+\left(\frac{x-5}{8}-1\right)+\left(\frac{x+6}{19}-1\right)=0\)

\(\Leftrightarrow\frac{x-13}{7}+\frac{x-13}{33}+\frac{x-13}{8}+\frac{x-13}{19}=0\)

\(\Leftrightarrow\left(x-13\right)\left(\frac{1}{7}+\frac{1}{33}+\frac{1}{8}+\frac{1}{19}\right)=0\)

Mà \(\frac{1}{7}+\frac{1}{33}+\frac{1}{8}+\frac{1}{19}\ne0\)

\(\Rightarrow x-13=0\Leftrightarrow x=13\)

\(\Leftrightarrow\)\(\dfrac{x}{7}-\dfrac{20}{7}+\dfrac{x}{33}-\dfrac{46}{33}+\dfrac{x}{8}-\dfrac{5}{8}+\dfrac{x}{19}+\dfrac{6}{19}=0\)

\(\dfrac{5016x}{35112}+\dfrac{1064x}{35112}+\dfrac{4389x}{35112}+\dfrac{1848x}{35112}=\dfrac{100320}{35112}+\dfrac{48994}{35112}-\dfrac{21945}{35112}+\dfrac{11088}{35112}\)

\(\dfrac{12317x}{35112}=\dfrac{160121}{35112}\)

\(12317x=160121\)

\(x=13\)

Làm cách này nhưng tớ thấy nó vẫn không tiến triển gì, thôi, qua cái này:

\(\dfrac{x-20}{7}+\dfrac{x-46}{33}+\dfrac{x-5}{8}+\dfrac{x+6}{19}=0\)

\(\dfrac{5016\left(x-20\right)+1064\left(x-46\right)+4389\left(x-5\right)+1848\left(x+6\right)}{35112}=0\)

\(5016x+1064x+4389x+1848x=100320+48944+21945-11088\)

\(12317x=160121\)

\(x=13\)

\(\Leftrightarrow\frac{x-20}{7}+1+\frac{x-46}{33}+1+\frac{x-5}{8}-1+\frac{x+6}{19}-1=0\)

\(\Leftrightarrow\frac{x-13}{7}+\frac{x-13}{33}+\frac{x-13}{8}+\frac{x-13}{19}=0\)

\(\Leftrightarrow\left(x-13\right)\left(\frac{1}{7}+\frac{1}{33}+\frac{1}{8}+\frac{1}{19}\right)=0\)

\(\Leftrightarrow x-13=0\)

\(\Leftrightarrow x=13\)

Ta có *chú ý: mk thêm bớt chỗ 1 nha\(\left(\dfrac{x-20}{7}+1\right)+\left(\dfrac{x-46}{33}+1\right)+\left(\dfrac{x-5}{8}-1\right)+\left(\dfrac{x+6}{19}-1\right)=0\)\(\Leftrightarrow\dfrac{x-20+7}{7}+\dfrac{x-46+33}{33}+\dfrac{x-5-8}{8}+\dfrac{x+6-19}{19}=0\)\(\Leftrightarrow\dfrac{x-13}{7}+\dfrac{x-13}{33}+\dfrac{x-13}{8}+\dfrac{x-13}{19}=0\)

\(\Leftrightarrow\left(x-13\right)\left(\dfrac{1}{7}+\dfrac{1}{33}+\dfrac{1}{8}+\dfrac{1}{19}\right)=0\)

\(\Rightarrow x-13=0\) (vì \(\dfrac{1}{7}+\dfrac{1}{33}+\dfrac{1}{8}+\dfrac{1}{19}\ne0\))

\(\Leftrightarrow x=13\)

Vậy tập nghiệm của pt là S=\(\left\{13\right\}\)

A, \(\frac{x+3}{2}\)-\(\frac{x-1}{3}\)=\(\frac{x+5}{6}\)+1

⇔ \(\frac{3\left(x+3\right)}{6}\)-\(\frac{2\left(x-1\right)}{6}\)=\(\frac{x+5}{6}\)+\(\frac{6}{6}\)

⇔ 3x+9-2x+2=x+5+6

⇔ 3x-2x-x=5+6-9-2

⇔0x=0 (luôn đúng với mọi x)

Vậy phương trình có vô số nghiêm:S=R

a) \(x+\frac{3}{2}-x-\frac{1}{3}=x+\frac{5}{6}+1\)

⇔ \(\frac{3}{2}-x-\frac{1}{3}=\frac{5}{6}+1\)

⇔ \(\frac{7}{6}-x=\frac{5}{6}+1\)

⇔ \(\frac{7}{6}-x=\frac{11}{6}\)

⇔ \(-x=\frac{11}{6}-\frac{7}{6}\)

⇔ \(-x=\frac{2}{3}\)

⇔ \(x=\frac{-2}{3}\)

Vậy tập nghiệm của pt là S = \(\left\{\frac{-2}{3}\right\}\)

1) x - 2 = -6

x = -6 + 2

x = -4

2) -5 . x - ( -3 ) =13

-5 . x = 13 + ( -3 )

-5 . x = 10

x = 10 : ( -5 )

x = -2

a: =>33+x=71-36=35

=>x=2

b: =>(2x+6)=200-64=136

=>2x=130

=>x=65

c: =>x-19=76

=>x=95

e: =>x+9=39

=>x=30

f: =>x-8=20

=>x=28

g: =>2x=5*9+49=45+49=94

=>x=47

1) ( x - 2 ) . ( x + 15 ) = 0

\(\Rightarrow\) x - 2 = 0 hoặc x + 15 = 0

* Nếu x - 2 = 0

x = 0 + 2

x = 2

* Nếu x + 15 = 0

x = 0 - 15

x = -15

Vậy x \(\in\) { 2 ; -15 }

2) ( 7 - x ) . ( x + 19 ) = 0

\(\Rightarrow\) 7 - x = 0 hoặc x + 19 = 0

* Nếu 7 - x = 0

x = 7 - 0

x = 7

* Nếu x + 19 = 0

x = 0 - 19

x = -19

Vậy x \(\in\) {7 ; -19}

dễ mà

13) –12(x -5) + 7(3 -x) = 5

→ -12x + 60  + 21 - 7x  = 5

→ -12x - 7x = 5 - 60 - 21

→ -19x = -76

→ x = -76 : ( - 19 )

→ x = 4

14) (x –2).(x + 4) = 0

→ ( x - 2 ) . ( x + 4 ) = 0 ↔ x - 2 = 0 hoặc x + 4 = 0 ( chọn 1 cách thôi nhé )

                                     → x = 0 + 2 = 2 hoặc x = 0 - 4 = -4

15) (x –2).( x + 15) = 0 ( làm giống câu trên )

16) (7–x).( x + 19) = 0 ( làm giống câu trên )

17) -5<x<1

→ x ϵ -4 ; -3 ; -2 ; -1 ; 0 

18) /x/<3

→ x ϵ -2 ; -1 ; 0 ; 1 ; 2

19) (x –3)(x –5) < 0

→ x - 3 . x - 5 < 0

→ 2x - 15 < 0

→ 2x < 0 + 15 = 15

→ x < 15 : 2 = 7,5

→ x ϵ ....... ( bạn tự ghi nhé )

20) 2x2–3 = 29( đề bài sai )

21) –6x –(–7) = 25

→ -6x + 7 = 25

→ -6x = 25 - 7 = 18

→ x = 18 : ( - 6 ) = -3

22) 46 –( x –11 ) = –48

→ 46 - x + 11 = -48

→ -x = -48 - 11 - 46 = -105

→ x = 105

khó quá mình bó tay

a: \(\dfrac{5}{3}\cdot\dfrac{7}{10}=\dfrac{5}{10}\cdot\dfrac{7}{3}=\dfrac{14}{3}>2\)

\(\dfrac{5}{7}:\dfrac{7}{10}=\dfrac{5}{7}\cdot\dfrac{10}{7}=\dfrac{50}{49}< 2\)

=>\(\dfrac{5}{3}\cdot\dfrac{7}{10}>\dfrac{5}{7}:\dfrac{7}{10}\)

b: \(\dfrac{4}{5}\cdot\dfrac{5}{6}=\dfrac{4}{6}=\dfrac{2}{3}\)

\(\dfrac{8}{9}:\dfrac{4}{3}=\dfrac{8}{9}\cdot\dfrac{3}{4}=\dfrac{8}{4}\cdot\dfrac{3}{9}=\dfrac{2}{3}\)

Do đó: \(\dfrac{4}{5}\cdot\dfrac{5}{6}=\dfrac{8}{9}:\dfrac{4}{3}\)

c: \(\dfrac{5}{11}\cdot\dfrac{33}{15}=\dfrac{5}{15}\cdot\dfrac{33}{11}=\dfrac{3}{3}=1\)

\(\dfrac{6}{17}\cdot\dfrac{34}{25}=\dfrac{34}{17}\cdot\dfrac{6}{25}=2\cdot\dfrac{6}{25}=\dfrac{12}{25}< 1\)

=>\(\dfrac{5}{11}\cdot\dfrac{33}{15}>\dfrac{6}{17}\cdot\dfrac{34}{25}\)

d: \(\dfrac{15}{19}\cdot\dfrac{38}{5}=\dfrac{15}{5}\cdot\dfrac{38}{19}=3\cdot2=6\)

\(\dfrac{15}{16}:\dfrac{3}{8}=\dfrac{15}{16}\cdot\dfrac{8}{3}=\dfrac{15}{3}\cdot\dfrac{8}{16}=\dfrac{5}{2}\)<6

=>\(\dfrac{15}{19}\cdot\dfrac{38}{5}>\dfrac{15}{16}:\dfrac{3}{8}\)