\(\left(x+40\right).15=75.12\)

\(\left(x+40\right).15=900\)

\(x+40=900:15\)

\(x+40=60\)

\(x=60-40\)

\(x=20\)

 \(\left(x+40\right)\cdot15=75\cdot12\)

\(\left(x+40\right)\cdot15=900\)

          \(\left(x+40\right)=900\div15\)

             \(x+40=60\)

                               \(x=60-40\)

                               \(x=20\)

1: \(=75\left(27+25-2\right)=75\cdot50=3750\)

2: \(=15\left(23+37\right)+55=15\cdot60+55=955\)

3: \(=36\cdot14+36\cdot17+36\cdot69\)

\(=36\cdot100=3600\)

4: \(=200\cdot\left(32+68\right)=200\cdot100=20000\)

( x+40 ) * 15 = 75 * 2

( x+40 ) * 15 = 150

( x+40 )  =   150 : 15

x + 40    = 10  

    x     =   10  - 40

    x     =   ( -30 )

HOk tốt

ai h minh minh h lai cho

( x + 40 ) * 15 = 75 * 2

( x + 40 ) * 15 = 150

x + 40 = 150 : 15

x + 40 = 10

x = 10 - 40

x = -30

a) 6x + 15 = 75

6x = 75 - 15

6x = 60

x = 60 : 6

x = 10

b) x - 12 = (-27)

x = (-27) + 12

x = -15

c) 23 + (x - 5) : 4 = 3⁸ : 3⁵

23 + (x - 5) : 4 = 3³

23 + (x - 5) : 4 = 27

23 + (x - 5) = 27 x 4

23 + (x - 5) = 108

x - 5 = 108 - 23

x - 5 = 85

x = 85 + 5

x = 90

a) 32 : (3.x - 2) = 8

3x - 2 = 32 : 8

3x - 2 = 4

3x = 4 + 2

3x = 6

x = 6 : 3

x = 2

b) 75 : (x - 18) = 25

x - 18 = 75 : 25

x - 18 = 3

x = 3 + 18

x = 21

c) (15 - 6.x) . 243 = 729

15 - 6x = 729 : 243

15 - 6x = 3

6x = 15 - 3

6x = 12

x = 12 : 6

x = 2

d) 4.(x - 12) + 9 = 17

4(x - 12) = 17 - 9

4(x - 12) = 8

x - 12 = 8 : 4

x - 12 = 2

x = 2 + 12

x = 14

e) 20 - 2.(x + 4) = 4

2(x + 4) = 20 - 4

2(x + 4) = 16

x + 4 = 16 : 2

x + 4 = 8

x = 8 : 2

x = 4

`32: ( 3xx x -2)=8`

`3xx x-2=32:8`

`3xx x-2=4`

`3 xx x=4+2`

`3xx x=6`

`x=6:3`

`x=2`

__

`75 : (x-18) =25`

`x-18=75:25`

`x-18= 3`

`x=3+18`

`x=21`

__

`(15-6 xx x ) xx 243 =729`

`15-6 xx x = 729 : 243`

`15-6 xx x = 3`

`6 xx x=15-3`

`6 xx x=12`

`x=12:6`

`x=2`

__

`4 xx (x-12)+9=17`

`4 xx (x-12)=17-9`

`4 xx (x-12)= 8`

`x-12=8:4`

`x-12=2`

`x=2+12`

`x=14`

__

`20-2xx(x+4)=4`

`2xx(x+4)=20-4`

`2xx(x+4)=16`

`x+4=16:2`

`x+4=8`

`x=8-4`

`x=4`

\(a,32:\left(3\times X-2\right)=8\\ 3\times X-2=32:8=4\\ 3\times X=4+2=6\\ X=\dfrac{6}{3}=2\\ Vậy:X=2\\ ---\\ b,75:\left(X-18\right)=25\\ X-18=75:25=3\\ X=3+18=21\\ Vậy:X=21\\ ---\\ c,\left(15-6\times X\right)\times243=729\\ 15-6\times X=729:243=3\\ 6\times X=15-3=12\\ X=\dfrac{12}{6}=2\\ Vậy:X=2\\ ---\\ d,4\times\left(X-12\right)+9=17\\ 4\times\left(X-12\right)=17-9=8\\ X-12=8:4=2\\ X=2+12=14\\ Vậy:X=14\\ ---\\ e,20-2\times\left(X+4+4\right)=4\\ 2\times\left(X+4\right)=20-4=16\\ X+4=16:2=8\\ X=8-4=4\\ Vậy:X=4\)

Phương pháp giải:

 Muốn tìm một số hạng ta lấy tổng trừ đi số hạng kia.

Lời giải chi tiết:

a) x + 4 = 40

    x = 40 − 4

    x = 36

b) 12 + x = 60

    x = 60 − 12

    x = 48

c) x + 15 = 30

    x = 30 − 15

    x = 15

c) \(x:15+42=15+26.8\)

   = \(x:15=181\)

   = \(x=181.15=2715\)

d) \(\left(x+40\right).15=75.24\)

   = \(x+40=\frac{75.24}{15}=120\)

   = \(x=120-40=80\)

C, x : 15 + 42 = 15 + 26 x 8

=>x : 15 + 42 = 15 + 208

=>x : 15 + 42 = 223

=>x : 15         = 223 - 42

=>x : 15         = 181

=>x                = 181 x 15

=>x                = 2715

Vậy x = 2715

c)x : 15+42=15+26 \(\times\) 8                               d)(x+40)\(\times\)15=75\(\times\)24

   x : 15+42=223                                                       (x+40)\(\times\)15=1800

   x : 15=223-42                                                        x+40=1800\(\div\)15

   x : 15=181                                                              x+40=120

   x =181 \(\times\)15                                                   x=120\(-\)40 

   x=2715                                                                   x=80