a. x - 1,27 = 13,5 : 4,5

=> x - 1,27 = 3

=> x = 3 + 1,27

=> x = 4,27

b. x + 18,7 = 50,5 : 2,5

=> x + 18,7 = 20,2

=> x = 20,2 - 18,7

=> x = 1,5

c. x * 12,5 = 6 * 2,5

=> x * 12,5 = 15

=> x = 15 : 12,5

=> x = 1,2 

a, 34+(21-x)=(3740-30)-(3740+10)

=>34+21-x=(3740-3740)-(30+10)

=>55-x=-40

=>x=55+40=95

b,(-329)+x=-63-(-17)

=>-329+x=-63+17

=>-329+x=-46

=>x=-46+329=283

a, 34 + ( 21 - x ) = ( 3740 - 30 ) - ( 3740 + 10 ) = 3710 - 3750  ;     b, ( -329 ) + x = -63 - ( -17)

    34 + ( 21 - x ) = - 40                                                                   ( -329 ) + x = -56

           ( 21 - x ) = -40 + 34                                                                           x = -56 - ( -329 )

           ( 21 - x ) = 6                                                                                     x = -385

                      x = 21 - 6 

Tick nha

                       x = 5

a)

x .12 , 5 = 1 , 2 + 25 % x .12 , 5 = 1 , 2 + 0 , 25 x .12 , 5 = 1 , 45 x = 1 , 45 : 12 , 5 x = 0 , 116

b)

0 , 4 x − 1 5 x = 3 4 2 5 − 1 5 x = 3 4 1 5 x = 3 4 x = 15 4

a, \(x-\frac{8}{9}=\frac{1}{3}\)

\(\Leftrightarrow x=\frac{1}{3}+\frac{8}{9}\)

\(\Leftrightarrow x=\frac{11}{9}\)

b, \(\frac{-4}{5}-\frac{8}{15}=\frac{-1}{3}-x\)

\(\Leftrightarrow\frac{-4}{3}=\frac{-1}{3}-x\)

\(\Leftrightarrow x=1\)

c, \(x+\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}=\frac{-37}{45}\)

Đặt \(A=\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}\)

\(A=\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{41}-\frac{1}{45}\)

\(A=\frac{1}{5}-\frac{1}{45}=\frac{8}{45}\)

Thay A vào phép tính

\(\Rightarrow x+\frac{8}{45}=\frac{-37}{45}\)

\(\Rightarrow x=-1\)

\(a,-\left(-94\right)+\left(67-x\right):2=\left(-34-14\right)\)

\(94+67-x:2=-48\)

\(161-x:2=-48\)

\(x:2=209\)

\(x=\frac{209}{2}\)

câu c thật ra là : - (- 34 - 23) = - x + 37

a. - (- 94) + (67 - x) : 2 = (- 34 - 14)

<=>94+(67-x):2=-48

<=>67-x:2=142

<=>x:2=-75

<=>x=-150

Vậy x=-150

b. 73 - (- 20 + 37) = x - (57 - 39)

<=>73+20-137=x-18

<=>x-18=-44

<=>x=-26

Vậy x=-26

c. - (- 34 - 23) = x + 37

34+23=x+37

<=>57=x+37

<=>x=20

Vậy x=20

34-y:5=12,5

y:5=34-12,5

y:5=21,5

y=21,5*5

y=10,5

6,35xy+3,65xy=50

(6,35+3,65)xy=50

10xy=50

xy=50:10=5

a=107,5

b=5

là xy hay là *y vậy

2735 + 434 + 329 + a - 735 - 34 - a + 171

= ( 2735 - 735 ) + ( 434 - 34 ) + ( 329 + 171 ) + ( a - a )

= 2000 + 400 + 500 + 0

= 2900

a) 8,76 x 34 + 67 x 8,76 - 8,76 

= 8,76 x 34 + 67 x 8,76 - 8,76 x 1

= 8,76 x ( 34 + 67 - 1 )

= 8,76 x       100

=            876

b) 12,5 x 3,27 + 67,3 x 12,5

=  12,5 x ( 3,27 + 67,3 )
=  12,5 x      70,57

=          882,125

c) 56,725 x 53,69 + 56,725 x 55,69 + 56,725

= 56,725 x 53,69 + 56,725 x 55,69 + 56,725 x 1

= 56,725 x ( 53,69 + 55,69 + 1 )

= 56,725 x      110,38

=      6261,13055

a) 8,76.34+67.8,76-8,76

=8,76.34+67.8,76-8,76.1

=8,76(34+67-1)

=8,76.100

=876

b)12,5.32,7+67,3.12,5

=12,5(32,7+67,3)

=12,5.100

=1250

c)56,725.53,69+56,725.55,69+56,725

=56,725.53,69+56,725.55,69+56,725.1

=56,725(53,69+55,69+1)

=56,725.109,39

=6205,14775

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