a, \(231-\left(x-6\right)=1339:13\)

\(\Leftrightarrow231-\left(x-6\right)=103\)

\(\Leftrightarrow x-6=128\)

\(\Leftrightarrow x=134\)

Vậy .....

b, \(70-5\left(2x-3\right)=45\)

\(\Leftrightarrow5\left(2x-3\right)=25\)

\(\Leftrightarrow2x-3=5\)

\(\Leftrightarrow2x=8\)

\(\Leftrightarrow x=4\)

Vậy ....

c, \(156-\left(x+61\right)=82\)

\(\Leftrightarrow x+61=74\)

\(\Leftrightarrow x=13\)

Vậy ....

d, \(6\left(5x+35\right)=330\)

\(\Leftrightarrow5x+35=55\)

\(\Leftrightarrow5x=20\)

\(\Leftrightarrow x=4\)

Vậy ......

e, \(936-\left(4x+24\right)=72\)

\(\Leftrightarrow4x+24=864\)

\(\Leftrightarrow4x=840\)

\(\Leftrightarrow x=210\)

Vậy ...

231-(x-6)=1339:13

237-x=103

=>x=237-103=134

Vậy x=134

70-5(2x-3)=45

70-10x+15=45

=>-10x=45-15-70=-40

=>x=4

Vậy x=4

Các caau sau tương tự nhé bn

1) 12.2.25+29.25+59.25

=24.25+29.25+59.25

=25(24+29+59)

=25.112

=2800

2) 25.(231+69)+72.(231+69)

=25.300+72.300

=300(25+72)

=300.97

=29100

3) 39.(250+87)+64.(240+97)

=39.337+64.337

=337.(39+64)

=337.103

=34711

4) 36.28+36.82+64.69+64.41

=36.(28+82)+64.(69+41)

=36.110+64.110

=110(36+64)

=110.100

=11000

Đăng từng bài thôi nha bạn.

1) 12 x 2 x 25 + 29 x 25 + 59 x 25

= 24 x 25 + 29 x 25 + 59 x 25

= 25 x ( 24 + 29 + 59 )

= 25 x 112

= 2800

2) 25 x ( 231 + 69 ) + 72 x ( 231 + 69 )

= 25 x 300 + 72 x 300

= ( 25 + 72 ) x 300 

= 29100

3)39 x ( 250 + 87 ) + 64 x ( 240 + 97 )

= 39 x 337 + 64 x 337

= ( 39 + 64 ) x 337

= 103 x 337

= 34711

tính nhanh 

1) 12.2.25+29.25+59.25

2) 25.(231+69)+72.(231+69)

3) 39.(250+87)+64.(240+97)

4) 36.28+36.82+64.69+64.41

1) 12 x 2 x 25 + 29 x 25 + 59 x 25

= 24 x 25 + 29 x 25 + 59 x 25

= 25 x ( 24 + 29 + 59 )

= 25 x 112

= 2800

2) 25 x ( 231 + 69 ) + 72 x ( 231 + 69 )

= 25 x 300 + 72 x 300

= ( 25 + 72 ) x 300 

= 29100

3)39 x ( 250 + 87 ) + 64 x ( 240 + 97 )

= 39 x 337 + 64 x 337

= ( 39 + 64 ) x 337

= 103 x 337

= 34711

125-82+7=50

40:5x8=64

20+70-30=60

72:9x10=80

câu a =3000

a, 28(231+69)+72(231+69)                  

=231+69.(28+72)

=231+69.100

=231+6900

=7131

b, 39(250+87)+64(240+97)

=39.337+64.337

=337(39+64)

=337.103

=34711

\(36.70+70.64=70\left(36+64\right)=70.100=7000\)

(Hình như sai dấu?)

70 x 64 mới tính nhanh được chứ 70 + 64 răng tính nhanh?

\(15\times\left(32-24\div x\right)-230=70\)

\(15\times\left(32-24\div x\right)=300\)

\(32-24\div x=20\)

\(24\div x=12\)

\(x=2\)

\(15\times\left(32-24:x\right)-230=70\)

\(15\times\left(32-24:x\right)=70+230\)

\(15\times\left(32-24:x\right)=300\)

\(32-24:x=300:15\)

\(32-24:x=20\)

\(24:x=32-20\)

\(24:x=12\)

\(x=24:12\)

\(x=2\)

\(#WendyDang\)

a.(64 - 32 ) :8 = 32 : 8 = 4 

b. 36 x 2 x7 + 36 x 86

= 36 x (14 + 86)

= 36 x 100

= 3600

   68:8 - 32 : 8

= ( 68 - 32): 8

=    36 : 8

=    4,5

72 x 7 + 36 x 86

= 72 x 7 + 36 x 2 x 43

= 72 x 7 + 72 x 43

= 72 x ( 7 + 43)

= 72 x 50

= 3600

8 x 6 = 48

8 x7 = 56

8 x 8 = 64

8 x 9 = 72

48 : 8 = 6

56 : 8 = 7

64 : 8 = 8

72 : 8 = 9