a) 150 : [17 - (2x - 3)] = 350

=> 17 - (2x - 3) = \(\frac{150}{350}=\frac{3}{7}\)

=> 2x - 3 = \(17-\frac{3}{7}=\frac{116}{7}\)

=> 2x = \(\frac{116}{7}+3\)

=> 2x = \(\frac{137}{7}\)

=> x = \(\frac{137}{7}:2=\frac{137}{14}\)

b) 4 . [105 - (x - 9)] - 486 = 0

=> 4. [105 - (x - 9)] = 486

=> 105 - (x - 9) = 243/2

=> x - 9 = \(105-\frac{243}{2}=-\frac{33}{2}\)

=> x = \(-\frac{33}{2}+9=-\frac{15}{2}\)

c) 1000 - 2{600 - 4.[198 - 7.(21 - 7)]}.x = 200

=> 1000 - 2{600 - 4.[198 - 7.14]}.x = 200

=> 1000 - 2{600 - 4.[198 - 98].x = 200

=> 1000 - 2{600 - 4.100}.x = 200

=> 1000 - 2{600 -400}.x = 200

=> 1000 - 2.200.x = 200

=> 2.200.x = 800

=> 400.x = 800

=> x = 2

Câu 2 :

a) 350 : [19 - (7x - 3)]  = 350

=> 19 - (7x - 3) = 1

=> 7x - 3 = 18

=> 7x = 21

=> x = 3

b) 7.[109 - (x - 9)] - 420 = 0

=> 7.[109 - (x - 9)] = 420

=> 109 - (x - 9) = 60

=> x - 9 = 49

=> x = 49 + 9 = 58

c) 254 - 2{200 - 4.[90 - 7.(19 - 9)]}.x = 54

=> 254 - 2{200 - 4.[90 - 7.10]}.x = 54

=> 254 - 2{200 - 4[90 - 70]} . x= 54

=> 254 - 2{200 - 4.20} . x = 54

=> 254 - 2{200 - 80}.x = 54

=> 254 - 2.120 . x=  54

=> 2.120.x = 200

=> 240.x = 200

=> \(x=\frac{5}{6}\)

5(x-9)=350

 X-9 = 350 : 5 = 70 

 X = 70 + 9 

X = 79

                   Tick Giúp mik nha

\(\text{a)}350:\left[19-\left(7x-3\right)\right]=350\)

\(\Rightarrow19-\left(7x-3\right)=1\)

\(\Rightarrow19-7x+3=1\)

\(\Rightarrow-7x=-21\)

\(\Rightarrow x=3\)

\(\text{b)}7.\left[109-\left(x-9\right)\right]-420=0\)

\(\Rightarrow7\left(109-x+9\right)=420\)

\(\Rightarrow118-x=60\)

\(\Rightarrow x=58\)

\(\text{c)}252-2\left\{200-4\left[90-7.\left(19-9\right)\right]\right\}.x=4\)

\(\Rightarrow2\left\{200-4\left[90-7.10\right]\right\}.x=250\)

\(\Rightarrow\left[200-4\left(90-70\right)\right].x=125\)

\(\Rightarrow\left[200-4.20\right].x=125\)

\(\Rightarrow120x=125\)

\(\Rightarrow x=\frac{125}{120}=\frac{25}{24}\)

\(\text{Xin điểm ạ}\)

350:[19-(7x-3)]=350

[19-(7x-3)]=350:350

[19-(7x-3)]=1

(7x-3)=19-1

(7x-3)=18

7x=18+3

7x=21

x=21:7

x=3

vậy x=3

7.[109-(x-19)]-420=0

7.[109-(x-19)]=0+420

7.[109-(x-19)]=420

[109-(x-19)]=420:7

[109-(x-19)]=60

(x-19)=109-60

(x-19)=49

x=49+19

x=58

vậy x=58

254-2{200-4.[90-7.(19-9)]}.x=4

254-2{200-4.[90-7.10]}.x=4

254-2{200-4.[90-70]}.x=4

254-2{200-4.20}.x=4

254-2{200-80}.x=4

254-2.120.x=4

254-240.x=4

240.x=254-4

240.x=250

x=250:240

x=25/24

vậy x=25/24

`5.(x-9)=350`

`x-9=350:5`

`x-9=70`

`x=70+9`

`x=79`

\(=>x-9=350:5\\ =>x-9=70\\ =>x=70+9\\ =>x=79\)

\(5\cdot\left(x-9\right)=350\\ \left(x-9\right)=350:5\\ \left(x-9\right)=70\\ x=70+9\\ x=79\)

\(5\left(x-9\right)=350\)

\(\Rightarrow x-9=70\Rightarrow x=79\)

Chúc bạn học tốt!!!

\(5(x-9)=350\)

\(5x-45=350\)

\(5x=395\)

\(x=79\)

\(5\left(x-9\right)=350\)

\(x-9=350:5\)

\(x-9=70\)

\(x=70+9\)

\(x=79\left(TM\right)\)

Vậy \(x=79\)

Chọn D

D

D

a: =>x-9=70

hay x=79

\(5\left(x-9\right)=350\\ \Rightarrow x-9=70\\ \Rightarrow x=79\\ \left(2x+2^5\right).8^{24}=8^{26}\\ \Rightarrow2x+32=8^{26}:8^{24}\\ \Rightarrow2x+32=8^2\\ \Rightarrow2x+32=64\\ \Rightarrow2x=32\\ \Rightarrow x=16\)

= 79

(x+1)+(x+3)+(x+5)+....+(x+19)=350

x                                          =350-(1+3+5+.................+19)

x                                          =350-100

x                                          =250:10

x                                          =25