=1000

1000 ht

1000 nha 

vì nhân 0 bằng 0 + 1000 

=1000

782  -   X   =  215                                                       36  : x   = 4

               X= 782 – 125                                                        x =36 : 4

                   X= 657                                                                              x = 9

4 < x < 21 5 x = 4

\(37\times46+37\times51+111\)

\(=37\times46+37\times51+37\times3\)

\(=37\times\left(46+51+3\right)\)

\(=37\times100\)

\(=3700\)

------------

\(172\times47+86\times8-34\times4\)

\(=172\times47+172\times4-34\times4\)

\(=172\times\left(47+4\right)-34\times4\)

\(=172\times51-34\times4\)

\(=172\times3\times17-17\times2\times4\)

\(=17\times\left(172\times3-2\times4\right)\)

\(=17\times\left(516-8\right)\)

\(=17\times508\)

\(=8636\)

------------

\(35\times215-35\times200-175\)

\(=35\times215-35\times200-35\times5\)

\(=35\times\left(215-200-5\right)\)

\(=35\times10\)

\(=350\)

------------

\(48\times56+28\times104\)

\(=48\times2\times28+28\times104\)

\(=28\times\left(48\times2+104\right)\)

\(=28\times200\)

\(=5600\)

88 800

261 304

không phải nhé

215-(4.x+15)=128

        (4.x+15)=215-128

        (4.x+15)=87

         4.x        =87-15

         4.x         =72

           x           =72:4=18

215-(4.x+15)=128

(4.x+15)=215-128 

4.x+15= 87 

4.x=87-15 

4.x=72
x=72:4 =18

 

Tìm x :

215 - ( 4x + 15 ) = 128

         ( 4x + 15 ) = 215 - 128

             4x + 15 = 87

                     4x = 87 - 15

                     4x = 72

                       x = 72 : 4

                       x = 18

a) \(37\times46+37\times51+111\)

\(=37\times46+37\times51+37\times3\)

\(=37\times\left(46+51+3\right)\)

\(=37\times100\)

\(=3700\)

b) \(35\times215-35\times210-175\)

\(=35\times215-35\times210-35\times5\)

\(=35\times\left(215-210-5\right)\)

\(=35\times0\)

\(=0\)

c) \(172\times47+86\times8-34\times4\)

\(=4\times\left(43\times47+86\times2-34\right)\)

\(=4\times\left(2021+172-34\right)\)

\(=4\times2159\)

\(=8636\)

d) \(48\times56+28\times104\)

\(=48\times56+56\times52\)

\(=56\times\left(48+52\right)\)

\(=56\times100\)

\(=5600\)

\(=-\left(215+x\right)+215=-9\\ -\left(215+x\right)=-224\\ x=-9\)

\(-215-x+215=9\\ -215-x=9-215\\ -215-x=-206\\ x=-215-\left(-206\right)\\ x=-9\)

hoặc ta có thể tính  như sau :

\(=-\left(215+x\right)+215=-9\\ \Rightarrow x+\left[\left(-215\right)+215\right]=-9\\ \Rightarrow x+0=-9\\ \Rightarrow x=-9\)

a)42.3-x=78

126-x=78

x=48

b)34.4+x=215

136+x=215

x=79

c)x.6=21

x=3,5

d)x:4=48

x=192

42x3-x=78

126-x=78

      x=126-78

      x=48

nhớ chọn cho mình

a) 42 * 3 - x = 78

     126 - x = 78

        x = 126 - 78

         x = 48

b) 34 * 4 + x = 215

       136 + x = 215

               x = 215 - 136

               x = 79

c) x * 6 = 18 + 3

    x * 6 = 21

      x = 21 : 6

        x = 3,5

d) x/4 = 8 * 6

    x/4 = 48

     x = 48 * 4

     x = 192