2 - \(x\) = 17 - (-5)

2 - \(x\) = 17 + 5

2 - \(x\) = 22

     \(x\) = 2 - 22

      \(x\) = -20

khó @gmail.com

làm ơn đi!!!!

x = 5 hoặc 3.8

đúng nha

a) (-125)+100+80+125+ 20=[(-125)+125]+100+(80+20)

=0+100+100=200

b)27+55+(-17)+(-55)=[27+(-17)]+[55+(-55)]

=10+0=10

c)(-92)+(-251)+(-8)+251=[(-92)+(-8)]+[(-251)+251]

=(-100)+0=-100

d)(-31)+(-95)+131+(-5)=[(-31)+131]+[(-95)+(-5)]

=100+(-100)=0

a) ( -125)+100+80+125+20

= [(-125) + 125] + (80+20) +100

= 0 + 100+100

=200

b) 27+55+(-17)+(-55)

= [27+(-17)]+[55+(-55)]

= 10+0

=10

c) (-92)+(-251)+(-8)+251

=[(-251)+251]+[(-92)+(-8)]

=0+(-100)

=-100

d) (-31)+(-95)+131+(-5)

=[(-31)+131]+[(-95)+(-5)]

=100+(-100)

=0

a) ( -125 ) + 100 + 80 + 125 + 20

= ( -125 + 125 ) + 100 + ( 80 + 20 )

= 0 + 100 + 100

= 200

b) 27 + 55 + ( -17 ) + ( -55 )

= ( -55 + 55 ) + [ 27 + ( -17 ) ]

= 0 + 10

= 10

c) ( -92 ) + ( -251 ) + ( -8 ) + 251

= ( -251 + 251 ) + [ ( -92 ) + ( -8 ) ]

= 0 + ( -100 )

= -100

d) ( -31 ) + ( -95 ) + 131 + ( -5 )

= [ 131 + ( -31 ) ] + [ ( -95 ) + ( -5 ) ]

= 100 + ( -100 )

= 0

224400

Lời giải:
$55\times 17\times 16\times 15=224400$

a) Ta có: \(3-\left(17-x\right)=-12\)

\(\Leftrightarrow3-17+x+12=0\)

\(\Leftrightarrow x-2=0\)

hay x=2

Vậy: x=2

b) Ta có: \(\left(2x+4\right)\left(10-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+4=0\\10-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=-4\\2x=10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=5\end{matrix}\right.\)

Vậy: \(x\in\left\{-2;5\right\}\)c) Ta có: \(\left|x-9\right|=-2+17\)

\(\Leftrightarrow\left|x-9\right|=15\)

\(\Leftrightarrow\left[{}\begin{matrix}x-9=15\\x-9=-15\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=24\\x=-6\end{matrix}\right.\)

Vậy: \(x\in\left\{24;-6\right\}\)

mai cậu đi học à

 \(\left|x-2\right|+\left|x-3\right|+\left|x-4\right|=2\)

\(\le\left|x\right|-\left|2\right|+\left|x\right|-\left|3\right|+\left|x\right|-\left|4\right|\)

\(x-2+x-3+x-4=2\)

\(\Leftrightarrow x+x+x-2-3-4=2\)

\(\Leftrightarrow x^3-2-3-4=2\)

\(x^3=2+4+3+2\)

\(x^3=11\)

\(x=\sqrt[3]{11}\)

\(2x-13=5-x\)

\(\Rightarrow2x+x=5+13\)

\(\Rightarrow3x=18\)

\(\Rightarrow x=6\)

\(-10⋮n-5\Rightarrow n-5\inƯ\left(-10\right)=\left\{\pm1;\pm2;\pm5;\pm10\right\}\)

\(\Rightarrow n\in\left\{6;4;7;3;10;0;15;-5\right\}\)

Vậy.............................

Đặng Tú Phương còn bài 1 làm sao bạn ?

Bài 1 nhân chia trước cộng trừ sau thôi

= 85 x (-18) - 18 x ( -15) = -1530 + 270 = -1260

`#040911`

`a)`

\(37 \times 7 - 17 \times 11 + 13 \times 37 + 17 \times 21\)

`= 37 \times (7 + 13) + 17 \times (21 - 11)`

`= 37 \times 20 + 17 \times 10`

`= 10 \times (37 \times 2 + 17)`

`= 10 \times 91`

`= 910`

`b)`

\(5^5 \times 5^2 \div 5^4 - 2^8 \div 2^4\)

`=`\(5^{5+2-4}-2^{8-4}\)

`= 5^3 - 2^4`

`= 125 - 16`

`= 109`

`c)`

\(3^{11}\times12+3^{12}\times5-3^{14}\)

`=`\(3^{11}\times\left(12+3\times5-3^3\right)\)

`=`\(3^{11}\times\left(12+15-27\right)\)

`=`\(3^{11}\times0=0\)

a) = 259 - 187 + 481 + 357

= 910

b) = 5⁷ : 5⁴ - 2⁴

= 5³ - 2⁴ 

= 125 - 16

= 109

Bài 2:

a, 37 x 7 - 17 x 11 + 13 x 37 + 17 x 21

= ( 37 x 7 + 13 x 37) + ( 17 x 21 - 17 x 11)

= 37 x ( 7 + 13) + 17 x ( 21 - 11)

= 37 x 20 + 17 x 10

= 740 + 170

= 910 

b, 5⁵ x 5² : 5⁴ - 2⁸ : 2⁴

= 5⁷: 5⁴ - 2⁴

= 5³ - 16

= 125 - 16

= 109

c, 3¹¹ x 12 + 3¹² x 5 - 3¹⁴

  3¹¹ x ( 12 + 3 x 5 - 13³)

= 3¹¹ x ( 12 + 15 - 3³)

= 3¹¹ x ( 27 - 27)

 = 3¹¹ x 0

= 0