a,64 x 25 + 35 x 25 +25=25.(64+35+1)=25.100=2500

b) 58 x 42 + 32 x 8 + 5=2436+256+5=2697

c) A =1 +2+3+4+...+100=(100+1)x[(100-1):1+1]:2=5050

\(64\times25+35\times25+25\)

\(=25\times\left(64+35+1\right)\)

\(=25\times100\)

\(=2500\)

                                         =25.100

                                         = 2500 

\(x-\left[\frac{50x}{100}+\frac{25x}{200}\right]=11\frac{1}{4}\)

\(x-\left[\frac{50x\cdot2}{200}+\frac{25x}{200}\right]=11\frac{1}{4}\)

\(x-\left[\frac{100x}{200}+\frac{25x}{200}\right]=11\frac{1}{4}\)

\(x-\frac{125x}{200}=11\frac{1}{4}\)

\(\frac{200x}{200}-\frac{125x}{200}=11\frac{1}{4}\)

\(\frac{200x-125x}{200}=11\frac{1}{4}\)

\(\frac{75x}{200}=11\frac{1}{4}\)

\(\frac{3x}{8}=11\frac{1}{4}\)

\(3x=11\frac{1}{4}\cdot8\)

\(3x=90\)

\(x=30\)

Vậy x = 30

cảm ơn bn nhé

kb ko 

Bài làm

-2x - ( x - 7 ) = 34 - ( -x + 25 ).

=> ( -2x ) - x + 7 = 34 + x - 25

=> -2x - x - x = 34 - 25 - 7

=> -4x = 2

=> x = 2/-4

=> x = -1/2

Vậy x = -1/2

\(-2x-\left(x-17\right)=34-\left(-x+25\right)\)

\(-2x-x+17=34+x-25\)

\(x-x-x=34+2-25\)

\(-3x=11\)

\(x=-\frac{11}{3}\)ko chắc :v 

-2x-(x-17)=34-(-x+25)

<=> -2x-x+17=3x+x-25

<=> -3x+17=4x-25

<=> -3x-4x=-25-17

<=> -7x=-42

<=> x=6

Vậy x=6

10 x 25 x 100 x 4

= 10 x ( 25 x 4 ) x 100

= 10 x 100 x 100

= 1000 x 100 = 100000

# Học tốt #

10x25x100x4 

= 10 x100 x(25x4) 

=1000 x 100 =

= 100000

Học giỏi nhé.

10 x 25 x 100 x 4 

= 100 x 100 x 4 x 25

= 10000 x 100

= 1000000

# MissyGirl #

25x25x10x25x20 = 3125000

=3125000 nha

3125000

\(\left(x-7\right)\left(x+2019\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-7=0\\x+2019=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=7\\x=-2019\end{cases}}\)

\(9-25=\left(7-x\right)-\left(25+7\right)\)

\(\Leftrightarrow-16=7-x-25-7\)

\(\Leftrightarrow-x=-16+25\)

\(\Leftrightarrow-x=9\)

\(\Leftrightarrow x=-9\)

\(2\left(4x-2x\right)-7x=15\)

\(\Leftrightarrow4x-7x=15\)

\(\Leftrightarrow x=-5\)

a ) 9 - 25 = ( 7 - x ) - ( 25 + 7 )

    9 - 25  =  7 - x - 25 - 7 

  9 - 25 - 7 + 25 + 7 = -x 

9        = - x

 => x = -9

Vậy x = -9

b) 2 . ( 4x - 2x ) - 7x = 15

    8x  - 4x - 7x          = 15 

-3x = 15

  x   =  15 : ( - 3 ) 

  x = -5 

Vậy x = -5

c ) ( x - 7 ). ( x + 2019 ) = 0

 => x - 7 = 0 hoặc x + 2019 = 0

   => x    = 7 hoặc x = - 2019 

 vậy x \(\in\){ 7 ; -2019 }

a. 9 - 25 = (7 - x) - (25 + 7)

=> -16 = 7 - x - 25 - 7

=> -16 = -x - 25

=> -x = 9

=> x = -9

b. 2 . (4x - 2x) - 7x = 15

=> 2 . 2x - 7x = 15

=> 4x - 7x = 15

=> -3x = 15

=> x = -5

c. (x - 7) . (x + 2019) = 0

=> x - 7 = 0 hoặc x + 2019 = 0

=> x = 7 hoặc x = -2019

128 - 3.(x+4) = 25-2

128 - 3.x - 12 = 23

128 - 12 -3.x = 23

116 - 3.x = 23

3.x = 93

x = 31

các bài còn lại bn dựa vào phần a mak lm nha!
 

128-3(x+4)=25-2

128-3(x+4)=23

       3(x+4)=128-23

       3(x+4)=105

         (x+4)=105:3

           x+4=35

           x    =35-4

           x    =31

128 - 3(x + 4) = 25 - 2

=> 128 - 3(x + 4) = 23

=> 3(x + 4) = 128 - 23

=> 3(x + 4) = 105

=> x + 4 = 105 : 3

=> x + 4 = 35

=> x = 35 - 4

=> x = 31

vậy_

15 - 6x = 3

=> 6x = 15 - 3

=> 6x = 12

=> x = 12 : 6

=> x = 2

vậy_

24 + 5x = 49

=> 5x = 49 - 24

=> 5x = 20

=> x = 20 : 5

=> x = 4

vậy_

219 - 7(x + 1) = 100

=> 7(x + 1) = 219 - 100

=> 7(x + 1) = 119

=> x + 1 = 119 : 7

=> x + 1 = 17

=> x = 17 -1 

=> x = 16

vậy_

t.i.c.k có được điểm đâu

<=>21-46+x=-18

<=>-25+x=-18

<=>x=7

21-(25-x+21)=-(25-7)

21-25+x-21=-18

-25+x=-18

x=(-18)-(-25)

x=7

   3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25

= 3,54 x ( 73 + 27 ) + 25 x ( 0,23 + 0,17 )

= 3,54 x 100 + 25 x 0,4

= 354 + 10

= 364

\(\text{3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25}\)

\(\text{= 3,54 x ( 73 + 27 ) + 25 x ( 0,23 + 0,17 )}\)

\(\text{= 3,54 x 100 + 25 x 0,4}\)

\(\text{= 354 + 10}\)

\(\text{= 364}\)

  3.54 x 73 + 0.23 x 25 + 3.54 x 27 + 0.17 x 25

= 3.54 x ( 73 + 27 ) + 25 x ( 0.23 + 0.17 )

=    3.54 x 100      + 25      x     1

= 354 + 25

= 364