a/( X-1)³ =125

=> (X-1)³ =5³

=> X-1=5 => X=6

câu b sai đề rồi bạn

a ) sai đầu bài

b) 15. { 32 : [ 6 - 5 + 5 ( 9: 3 )]}

= 15 . { 32 : [ 6 - 5 + 5 . 3 ]}

= 15 . { 32 : [ 6 - 5 + 15 ] }

= 15 . { 32 : [ 1 +15 ] }

= 15 . { 32 : 16 }

= 15 . 2

= 30

bài 2:

a) 14

b)1024

Bài1:

b)15.{32:[6-5+5(9:3)]}

=15.{32:[6-5+5.3]}

=15.{32:[6-5+15]}

=15.{32:[1+15]}

=15.{32:16}

=15.2

=30

a 720 :[ 41 -(2x -5)]=8 . 5

720 :[41 -(2x-5)]=40

[41- (2x -5)]=720:40

[41-(2x-5)]=18

(2x-5)=41-18

2x-5=23

2x=23+5

2x=28

x=28:2

x=14

b 70-5(x-3)=45

5(x-3)=70-45

5(x-3)=25

x-3=25:5

x-3=5

x=5+3

x=8

c 2.x-138=8.9

2.x-138=72

2.x=138+72

2.x=210

x=210:2

x=105

720 : [ 41 -(2X -50)] = 40

         41 - (2X - 50) = 720 : 40

         41 - (2X - 50) = 18

                 2X - 50  = 41 - 18

                 2X - 50  = 23

                 2X         = 23 + 50

                 2X         =  73

                 2X         =  73 :2

                 2X         =  36,5

70 - 5 . (X - 3) = 50

       5 . (X -3 ) = 70 - 50

       5 . (X - 3) =  20

             X - 3  = 20 : 5

             X - 3  =  4

             X       = 4 + 3

            X        =  7

2.X - 138 = 2³ .5

2.X - 138 = 40

2.X -       = 40 + 138

2.X         =  178

   X         =  178 : 2

   X         =  89

tìm x

a) 7(x-4)³+30=219

7(x-4)³=219-30

7(x-4)³=189

(x-4)³=189:7

(x-4)³=27

(x-4)³=3³

x-4=3

x=3+4

x=7

b,720:[41(2.x-5)]=40

41(2.x-5)=720:40

41(2.x-5)=18

2.x-5=18:41

2.x-5=\(\frac{18}{41}\)

2.x=\(\frac{18}{41}\)+5

2.x=\(\frac{223}{41}\)

x=\(\frac{223}{41}\):2

x=\(\frac{223}{82}\)

Tính

c)100:{250:[450-(4.5³-2².25]}

=100:{250:[450-(4.125-4.25]}

=100:{250:[450-[500-100]}

=100:{250:[450-400]}

=100:{250:50}]

=100:50

=2

(li-ke cho mình nha)

1)63

157

30

50

2)x=9

x=2016

x=14

x=977

3)678384

\(\left(2x+1\right)^3=7^3\)(mk nghĩ là 343)

=>2x+1=7

=>x=3

b)\(2^x\left(2^2-1\right)=96\)

\(2^x.3=96\Rightarrow2^x=2^5\)

\(\Rightarrow x=5\)

c) \(41-\left(2x-5\right)=720:2^3:5\)

\(41-2x+5=18\)

\(-2x=-28\)

=>x=14

câu a bn ghi là 243 nhưng căn bậc 3 của 243 lẻ nên mk thay vào là 343.

bn vào đg link này nha:https://olm.vn/hoi-dap/detail/55779839285.html

a)\(\left(x-1\right)^3=8\)

\(\Leftrightarrow\left(x-1\right)^3=\left(2\right)^3\)

\(\Leftrightarrow x-1=2\)

\(\Leftrightarrow x=3\)

b)\(2^{x+2}-2^x=96\)

\(\Leftrightarrow2^x.2^2-2^x=96\)

\(\Leftrightarrow2^x\left(2^2-1\right)=96\)

\(\Leftrightarrow2^x=32=2^5\)

\(\Leftrightarrow x=5\)

c)\(\left(2x+1\right)^3=343\)

\(\Leftrightarrow\left(2x+1\right)^3=7^3\)

\(\Leftrightarrow\left(2x+1\right)=7\)

\(\Leftrightarrow x=3\)

d)\(720:\left[41-\left(2x-5\right)\right]=2^3.5\)

\(\Leftrightarrow720:\left[46-2x\right]=40\)

\(\Leftrightarrow46-2x=18\)

\(\Leftrightarrow2x=28\)

\(\Leftrightarrow x=14\)