\(56.\left(15+23\right)-15.\left(23+56\right)\)

\(=\left(56.15+56.23\right)-\left(15.23+15.56\right)\)

\(=56.15+56.23-15.23-15.56\)

\(=\left(56.15-56.15\right)+\left(56.23-15.23\right)\)

\(=0.\left[23.\left(56-15\right)\right]\)

\(=23.41\)

\(=943\)

a)  56.[ 15 + 23 ] - 15.[ 23 + 56 ]

=   56. 38       -  15.  79

=      2128  -   1185

=           943

b)   12.[ 47 - 23 ]  +  23. [12 + 47]

 =    12 .  24        +   23.    59

 =         288         +       1357

=                   1645

~ chúc bạn hok tốt nha ~ ^_^

\(445-52+155+452\\ =\left(445+155\right)+\left(452-52\right)\\ =600+4000\\ =1000\\ 102\cdot55-102\cdot73+51\cdot36\\ =102\cdot\left(55-73\right)+51\cdot36\\ =102\cdot\left(-18\right)+102\cdot18\\ =0\\ 4\cdot5\cdot2\cdot25\cdot5-1000\\ =5000-1000\\ =4000\\ 8782-291\cdot13\\ =4999\\ 254+\left\{38\cdot\left[\left(42-16\right):2\right]\right\}\\ =254+\left[38\cdot\left(26:2\right)\right]\\ =254+\left(38\cdot13\right)\\ =748\\ \left(2791\cdot34+7882:14\right)\cdot0+1510-510:2\\ =1510-255\\ =1255\)

a. \(445-52+155+452=\left(445+155\right)+\left(452-52\right)=600+400=1000\)

b. \(102\cdot55-102\cdot73+51\cdot36=102\left(55-73+18\right)=102\cdot0=0\)

c.\(4\cdot5\cdot2\cdot25\cdot5-1000=4\cdot25\cdot5\cdot5\cdot2-1000=100\cdot50-1000=5000-1000=4000\)

d. \(8782-291\cdot13=8782-3783=4999\)

e. \(254+\left\{38\left[\left(42-16\right)\div2\right]\right\}=254+\left\{30\cdot13\right\}=254+494=748\)

f. \(\left(2791\cdot34+7882\div14\right)\cdot0+1510-510\div2=0+1510-255=1255\)\

3 x ( X -18) +23 = 59

3 x ( X -18 )       = 59 - 23

3 x ( X - 18)       =    36

        X - 18         = 36 : 3

         X - 18        =    12

          X         = 12 + 18

          X           = 30

k nha

3x(x-180+23=59

3x-18=59-23

3x-18=36

3x=36+18

3x=54

x=54:3

x=18

Vậy x=18

Bài làm :

\(a,2.x-3=185\)

\(2.x=185+3\)

\(2.x=188\)

\(x=94\)

\(b,357-\left(2.x-23\right)=122\)

\(2.x-23=357-122\)

\(2.x-23=235\)

\(2.x=258\)

\(x=129\)

\(c,152+\left(x+231\right):2=358\)

\(\left(x+231\right):2=358-152\)

\(\left(x+231\right):2=206\)

\(x+231=412\)

\(x=181\)

Học tốt nhé

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

4177

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4177

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\(x\left(x+y+z\right)=10\)    (1)

\(y\left(y+z+x\right)=25\)  (2)

\(z\left(z+x+y\right)=-10\)  (3)

Lấy  (1) + (2) + (3)  theo vế ta có:

      \(x\left(x+y+z\right)+y\left(y+z+x\right)+z\left(z+x+y\right)=10+25-10\)

\(\Leftrightarrow\)\(\left(x+y+z\right)^2=25\)

\(\Leftrightarrow\)\(x+y+z=\pm\sqrt{25}=\pm5\)

Nếu  \(x+y+z=5\) thì:    \(\hept{\begin{cases}x=2\\y=5\\z=-2\end{cases}}\)

Nếu   \(x+y+z=-5\)thì   \(\hept{\begin{cases}x=-2\\y=-5\\z=2\end{cases}}\)

Vậy...