\(\frac{x-1}{99}+\frac{x-2}{98}+\frac{x-3}{97}+\frac{x-4}{96}+\frac{x-5}{95}=5\)

\(\Rightarrow\left(\frac{x-1}{99}-1\right)+\left(\frac{x-2}{98}-1\right)+\left(\frac{x-3}{97}-1\right)+\left(\frac{x-4}{96}-1\right)+\left(\frac{x-5}{95}-1\right)\)\(=5-1-1-1-1-1\)

\(\Rightarrow\frac{x-100}{99}+\frac{x-100}{98}+\frac{x-100}{97}+\frac{x-100}{96}+\frac{x-100}{95}=0\)

\(\Rightarrow\left(x-100\right).\left(\frac{1}{99}+\frac{1}{98}+\frac{1}{97}+\frac{1}{96}+\frac{1}{95}\right)=0\)

Mà \(\frac{1}{99}+\frac{1}{98}+\frac{1}{97}+\frac{1}{96}+\frac{1}{95}\ne0\)

\(\Rightarrow x-100=0\)

\(\Rightarrow x=100\)

Vậy x=100

Chúc bạn học tốt

`[ ( 2 xx x - 11 ) : 3 + 1 ] xx 5 = 20`

`( 2 xx x - 11 ) : 3 + 1=20:5`

`( 2 xx x - 11 ) : 3 + 1=4`

`( 2 xx x - 11 ) : 3 =4-1`

`( 2 xx x - 11 ) : 3 =3`

`2xx x -11=3xx3`

`2xx x -11=9`

`2xx x =9+11`

`2 xx x=20`

`x=20:2`

`x=10`

Vậy `x=10`

`b,  x - 96 = ( 443 - x ) - 15`

`x-96=443-x-15`

` x+x=443-15+96`

`2x=524`

`x=524:2`

`x= 262`

Vậy `x=262`

\(#Nqoc\)

`a)`

\([ ( 2 \times x - 11 ) \div 3 + 1 ] \times 5 = 20\)

`(2 \times x - 11) \div 3 + 1 = 20 \div 5`

`(2 \times x - 11) \div 3 + 1 = 4`

`(2 \times x - 11) \div 3 = 4  - 1`

`(2 \times x - 11) \div 3 = 3`

`2 \times x - 11 = 3 \times 3`

`2 \times x - 11 = 9`

`2 \times x = 9 + 11`

`2 \times x = 20`

`x = 20 \div 2`

`x = 10`

Vậy, `x = 10`

`b)`

\(x - 96 = ( 443 - x ) - 15\)

`x - 96 = 443 - x - 15`

`x - 96 = 428 - x`

`x = 428 - x + 96`

`x = 524 - x`

`x - 524 + x = 0`

`(x + x) - 524 = 0`

`2x - 524 = 0`

`2x = 524`

`x = 524 \div 2`

`x = 262`

Vậy, `x = 262.` 

a) nếu tích = 0 => một trong hai số hạng = 0 

nếu x-5=0 => x=5 

nếu x-7=0 => x= 7 

=> x thuộc {5;7}

b)96-3(x+1)=42

3.(x+1)=96-42=54 

x+1=54:3=18 

x=18-1=17 

các bạn cho mk vài li-ke cho tròn 950 với 

(x-5).(x-7)=0

=>x-5=0 =>x=5

hoac   x-7=0=>x=7

96-3.(x+1)=42

3.(x+1)     =96-42=54

  (x+1)      =54/3=18

x              =18-1

x=7

(x-5).(x-7)=0

->x-5=0(hay)(1)

  x-7=0(2)

giải1

x-5=0

->x=0-5=-5

giải2

x-7=0

->x=0-7=-7

->x thuộc{-5,-7}

Vậy x thuoc {-5.-7}

\(96-3\left(x+1\right)=0\)

\(96-3x-3=0\)

\(93-3x=0\)

\(3x=93\)

\(x=31\)

vậy \(x=31\)

405:(5x-15)=0 <=> 5x-15 =405

<=> 5x=420 => x=84

HS tự làm

a, 5(x – 7) = 0

x – 7 = 0

x = 7

b, 95 – 5(x+2) = 45

5(x+2) = 40

x+2 = 8

x = 6

c,  6 2 x + 2 3 + 40 = 100

6(2x+8) = 60

2x+8 = 10

x = 1

d, 3(3x+9)+6 = 96

3(3x+9) = 90

3x+9 = 30

3x = 27

x = 9

e,  2 6 + 5 + x = 3 4

5+x = 81–64

5+x = 17

x = 12

       \(\frac{2x+1}{4-x}=\frac{x-1}{5}\)

\(\Rightarrow\)\(5.\left(2x+1\right)=\left(4-x\right).\left(x-1\right)\)

\(\Rightarrow\)\(10x+5=2x-4\)

\(\Rightarrow\)\(10x-2x=-4-5\)

\(\Rightarrow\)\(8x=-9\)

\(\Rightarrow\)\(x=-\frac{9}{8}\)

\(\frac{x-2}{99}+\frac{x-3}{98}=\frac{x-4}{97}+\frac{x-5}{96}\Leftrightarrow\frac{x-2}{99}-1+\frac{x-3}{98}-1=\frac{x-4}{97}-1+\frac{x-5}{96}-1\)

<=>\(\frac{x-101}{99}+\frac{x-101}{98}=\frac{x-101}{97}+\frac{x-101}{96}\)

<=>\(\left(x-101\right)\left(\frac{1}{99}+\frac{1}{98}-\frac{1}{97}-\frac{1}{96}\right)=0\)

<=>x-101=0 \(\left(\frac{1}{99}+\frac{1}{98}-\frac{1}{97}-\frac{1}{96}\ne0\right)\)

<=>x=101

101