Ko muốn làm đâu thoi thì giúp bn

\(\left(111-x\right)+7^2=149\)

\(\Rightarrow\left(111-x\right)=49=149\)

\(\Rightarrow111-x=100\)

\(\Rightarrow x=11\)

\(\left|x\right|+18=163+\left(-45\right)\)

\(\Rightarrow\left|x\right|+18=163-45\)

\(\Rightarrow\left|x\right|+18=91\)

\(\Rightarrow\orbr{\begin{cases}x=73\\x=-73\end{cases}}\)

\(7^{x-4}.6=2058\)

\(\Rightarrow7^{x-4}=2058:6\)

\(\Rightarrow7^{x-4}=343\)

\(\Rightarrow7^{x-4}=7^3\)

\(\Rightarrow x-4=3\)

\(\Rightarrow x=7\)

84 : x ; 126 : x và 7 <\(< \)x \(\le\)21

Vì 84 : x ; 126 : x \(\Rightarrow x\inƯCLN;x\inℕ^∗\)  

\(84=2^2.3.7\)

\(126=2.3^2.7\)

Sai đề

a,38.37+38.73-110.29

= 38 . ( 37 + 73 ) -110.29

=38 . 110 - 110.29

= 110 . ( 38 - 29 )

= 110. 9

=990

k mình nha Nguyễn Hà My linh 

38.37+38.73-110.29=38.(37+73)-110.29

                                =38.110-110.29

                                =110.(38-29)

                                =110.9

                                =990

Chúc học tốt nha!!!

\(\text{a/96-3(x+1)=42}\)

\(3\left(x+1\right)=54\)

\(x+1=54:3\)

\(x+1=18\)

\(\Rightarrow x=17\)

\(\text{b/2.x-18=20}\)

\(2x=38\)

\(x=38:2\)

\(x=19\)

\(\text{c/134-5.(x+4)=34}\)

\(5\left(x+4\right)=100\)

\(x+4=100:5\)

\(x+4=20\)

\(\Rightarrow x=16\)

học tốt

a) 96-3(x+1)=42

3(x+1)=96-42

3(x+1)=54

x+1=54:3

x+1=18

x=18-1

Vậy x=17

b) 2x-18=20

2x=20+18

2x=38

x=38:2

x=19

Vậy x=19.

c) 134-5(x+4)=34

5(x+4)=134-34

5(x+4)=100

x+4=100:5

x+4=20

x=20-4

x=16

Vậy x=16.

a) 96-3(x+1)=42

          3(x+1)=96-42

          3(x+1)=54

               x+1=54:3

               x+1=18

                   x=18-1

                   x=17

Vậy x=17

b)2.x-18=20

   2.x     =20+18

   2.x     =38

      x     =38:2

      x     =19

Vậy x=19

c)134-5.(x+4)=34

          5.(x+4)=134-34

          5.(x+4)=100

              x+4 =100:5

              x+4 =20

                  x =20-4

                  x =16

Vậy x=16
 

\(12:\left\{390:\left[500-\left(5^3+7^2.5\right)\right]\right\}\)

\(=12:\left\{390:\left[500-\left(125+49.5\right)\right]\right\}\)

\(=12:\left\{390:\left[500-\left(125+245\right)\right]\right\}\)

\(=12:\left[390:\left(500-370\right)\right]\)

\(=12:\left(390:130\right)\)

\(=12:3\)

\(=4\)

   12 : { 390 : [ 500 - ( 5³  + 7²  . 5 ) ] }

= 12 : { 390 : [ 500 - (125 + 49 . 5 ) ] }

= 12 : { 390 : [ 500 - (125 + 245 ) ] }

= 12 : { 390 : [ 500 - 370] }

= 12 : { 390 : 130}

= 12 : 3

= 4

Xin mời XD

a) 5^x  . 5¹⁵ = 5²¹

=> 5^x = 5²¹ : 5¹⁵

=> 5^x = 5⁶

=> x = 6

a) 5^x  . 5¹⁵ = 5²¹

    5^x         = 5²¹ : 5¹⁵

    5^x         = 5⁶

=> x = 6

b) 7^x : 49 = 75

    7^x       = 75 . 49

     7^x      = 3675

x - 4867 = (175 . 2 - 5 . 70): 25 .23

x - 4867 = ( 5².7.2 - 5².7.2) : 25.23

x - 4867 = 0 : 25 . 23 = 0

x = 0 + 4867

x=4867.

x - 4867 = (175 . 2 - 5 . 70) : 25 .23

x - 4867 = (5².7.2 - 5².7.2) : 25.23

x - 4867 = 0 : 25 . 23 = 0

x = 0 + 4867

x = 4867

\(\frac{-1997\cdot1996+1}{-1995\cdot\left(-1997\right)+1996}\)

\(=\frac{-1997\cdot\left(1995+1\right)+1}{1995\cdot1997+1996}\)

\(=\frac{-1997\cdot1995+\left(-1997\right)+1}{1995\cdot1997+1996}\)

\(=\frac{-1997\cdot1995+\left(-1996\right)}{1995\cdot1997+1996}\)

\(=-1\)

\(\frac{-1997.1996+1}{-1995.\left(-1997\right)+1996}\)

\(=\frac{-1997.1996+1}{1995.1997+1996}\)

\(=\frac{-1997.\left(1995+1\right)+1}{1995.1997+1996}\)

\(=\frac{-1997.1995+-1997+1}{1995.1997+1996}\)

\(=\frac{1995.-1997+-1996}{1995.1997+1996}\)

\(=\frac{-\left(1995.1997+1996\right)}{1995.1997+1996}\)

\(=-1\)