\(a,91-5.\left(5+x\right)=61\\ \Rightarrow=5.\left(5+x\right)=30\\ \Rightarrow5+x=6\\ \Rightarrow x=1.\\ b,\left[195-\left(3x-27\right)\right].39=4212\\ \Rightarrow195-\left(3x-27\right)=108\\ \Rightarrow3x-27=87\\ \Rightarrow3x=114\\ \Rightarrow x=38.\)

\(91-5.\left(5+x\right)=61\)

\(\Rightarrow5.\left(5+x\right)=91-61\)

\(\Rightarrow5.\left(5+x\right)=30\)

\(\Rightarrow5+x=\dfrac{30}{5}=6\)

\(\Rightarrow x=6-5=1\)

\(\left[195-\left(3x-27\right)\right].39=4212\)

\(\Rightarrow195-3x+27=\dfrac{4212}{39}=108\)

\(\Rightarrow222-3x=108\)

\(\Rightarrow3x=222-108=114\)

\(\Rightarrow x=\dfrac{114}{3}=38\)

$91-5.\left(5+x\right)=61$

$\Rightarrow 5.\left(5+x\right)=91-61$

$\Rightarrow 5.\left(5+x\right)=30$

⇒5+�=305=6⇒5+x=530​=6

$\Rightarrow x=6-5=1$

$\left[195-\left(3x-27\right)\right].39=4212$

⇒195−3�+27=421239=108⇒195−3x+27=
​4212/39=108

$\Rightarrow 222-3x=108$

$\Rightarrow 3x=222-108=114$

⇒�=1143=38⇒x=114/3
​=38

\(\left[195-\left(3x-27\right)\right]\cdot39=4212\)

\(\Rightarrow\left(195-3x+27\right)\cdot39=4212\)

\(\Rightarrow\left(-3x+222\right)\cdot39=4212\)

\(\Rightarrow-3x+222=\dfrac{4212}{39}\)

\(\Rightarrow-3x+222=108\)

\(\Rightarrow3x=222-108\)

\(\Rightarrow3x=114\)

\(\Rightarrow x=\dfrac{114}{3}\)

\(\Rightarrow x=38\)

=>[195-(3x-27)]=4212:39=108

=>3x-27=195-108=87

=>3x=27+87=114

=>x=38

[195-(15x-27).39=4212

195-(15x-27)=4212 : 39

195-(15x-27)=108

15x-27=195-108

15x-27=87

15x=87+27

15x=114

x=114:15

x=38/5

x=7,6

k đúng cho m nha bạn !

Đề thiếu bạn ạ.

thank you quang anh nguyễn

a,91-5(5+x)=61

=>25+5x=91-61=30

=>5x=30-25=5

=>x=1

b,\([\left(x+34\right)-50]\)x2=56

=>(x+34)-50=56:2=28

=>x+34=28+50=78

=>x=78-34=44.

c,1045-\([2015-\left(3x-24\right)]\)=5

=>2015-(3x-24)=1045-5=1040

=>3x-24=2015-1040=975

=>3x=975+24=999

=>x=999:3=333

d,\([195-\left(3x-27\right)]\)x39=4212

=>195-(3x-27)=4212:39=108

=>3x-27=195-108=87

=>3x=87+27=117

=>x=39

e,30-3(x-2)=18

=>30-3x+6=18

=>30-3x=18-6=12

=>3x=30-12=18

=>x=18:3=6

a) \(...\Rightarrow5\left(5+x\right)=91-61=30\)

\(\Rightarrow\left(5+x\right)=30:5=6\Rightarrow x=6-5=1\)

b) \(...\Rightarrow\left(x+34\right)-50=56:2=28\)

\(\Rightarrow\left(x+34\right)=28+50=78\Rightarrow x=78-34=44\)

c) \(...\Rightarrow2015-\left(3x-24\right)=1045-5=1040\)

\(\Rightarrow\left(3x-24\right)=2015-1040=975\)

\(\Rightarrow3x=975+24=999\Rightarrow x=999:3=333\)

d) \(...\Rightarrow195-\left(3x-27\right)=4212:39=108\)

\(\Rightarrow\left(3x-27\right)=195-108=87\)

\(\Rightarrow3x=87+27=114\Rightarrow x=114:3=38\)

e) \(...\Rightarrow3\left(x-2\right)=30-18=12\Rightarrow x-2=12:3=4\)

\(\Rightarrow x=4+2=6\)

\(1734:17=102x17:17=102x1=102\)

\(\left(x-7\right)\)\(2-26=13x17-13x7=13\left(17-7\right)=13x10=130\)

\(\left(x-7\right)2=130+26=156\)

\(x-7=156:2=78\)

\(x=78+7=85\)

\(=>x=85\)

\(195-\left(15x+27\right)=4212:39=108\)

\(15x+27=195-108=87\)

\(15x=87-27=60\)

\(x=60:15=4\)

\(=>x=4\)

- Tính nhẩm
1734 : 17 = 102

- Tìm x
(x - 7) .2 - 26 = 13.17 - 13.7
(x - 7) .2 - 26 = 13.(17 - 7)
(x - 7) .2 - 26 = 13. 10
(x - 7) .2 - 26 = 130
(x - 7) .2         = 130 + 26
(x - 7) .2         = 156
(x - 7)             = 156 : 2
(x - 7)             = 78
 x                    = 78 + 7
 x                    = 85
___________________
195 - (15x + 27) .39 = 4212         (dấu "[" đặt ở đấu tiên nên không cần thiết)
         (15x + 27) .39 = 195 - 4212
         (15x + 27) .39 = -4017
         (15x + 27)       = -4017 : 39
         (15x + 27)       = -103
          15x                 = -103 -27
          15x                 = -130
              x                 = -130 : 15
              x                 = -26/3
 

a) \(1045:\left[215-\left(3x-24\right)\right]=5\)

\(\Rightarrow215-\left(3x-24\right)=1045:5\)

\(\Rightarrow215-\left(3x-24\right)=209\)

\(\Rightarrow3x-24=215-209\)

\(\Rightarrow3x-24=6\)

\(\Rightarrow3x=6+24\)

\(\Rightarrow3x=30\)

\(\Rightarrow x=30:3\)

\(\Rightarrow x=10\)

Vậy x = 10

b) \(\left[195-\left(15x+27\right)\right]\times39=4212\)

\(\Rightarrow195-\left(15x+27\right)=4212:39\)

\(\Rightarrow195-\left(15x+27\right)=108\)

\(\Rightarrow15x+27=195-108\)

\(\Rightarrow15x+27=87\)

\(\Rightarrow15x=87-27\)

\(\Rightarrow15x=60\)

\(\Rightarrow x=60:15\)

\(\Rightarrow x=4\)

Vậy x = 4

_Chúc bạn học tốt_

\(95-\left(3x-27\right).39=4212\)

\(95-\left(3x-27\right)=108\)

\(3x-27=-13\)

\(3x=14\)

\(x=\dfrac{14}{3}\)

\(95-\left(3x-27\right).39=4212\)

\(95-\left(3x-27\right)=4212:39\)

\(95-\left(3x-27\right)=108\)

\(3x-27=95-108\)

\(3x-27=-13\)

\(3x=-13+27\)

\(3x=14\)

\(x=14:3\)

\(x=\dfrac{14}{3}\)

Vậy \(x=\dfrac{14}{3}\)

\(a.\left[\left(x+34\right)-50\right].2=56\\ \Leftrightarrow\left(x+34\right)-50=28\\ \Leftrightarrow x+34=78\\ \Rightarrow x=44\)

\(b.1045-\left[215-\left(3x-24\right)\right]=5\\ \Leftrightarrow215-\left(3x-24\right)=1040\\ \Leftrightarrow3x-24=-825\\ \Leftrightarrow3x=-801\\ \Rightarrow x=-267\)

\(c.\left[195-\left(15x-27\right)\right].39=4212\\ \Leftrightarrow195-\left(15x-27\right)=108\\ \Leftrightarrow15x-27=87\\ \Leftrightarrow15x=114\\ \Rightarrow x=7,6\)

a) [(x+34)] - 50] . 2 = 56

=x+34-50=56:2

=> x+34-50=28

->x=28+50-34

-> x=44

b,1045 - [ 215 - ( 3x - 24 )] = 5

1045-(215-3x+24)=5

1045-215+3x-24=5

1045-215-24-5=-3x

-> 801=-3x-> x=801:(-3)=-267

,c) [ 195 - ( 15x - 27)] . 39 = 4212

(195-15x+27).39=4212

(195-15x+27)=4212/39=108

195+27-108=15x

114=15x-> x=114/15=7,6

-

a) [(x+34)] - 50] . 2 = 56

(x+34)] - 50=56:2

(x+34)] - 50=28

(x+34)=28+50

x+34=78

x=78-34

x=44

Vậy...

câu b có sai đề bài ko vậy