7/x=y/27=-42/54=-7/9

7/x=-7/9 nên x=-9

y/27=-7/9=-21/27 nên y=-21

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42 * 6 - 42,9 * 4 - 42,9

252 - 42,9 * 4 - 42,9

252 - 42,9 * 4 - 42,9 * 1

252 - 42,9 * ( 4 - 1)

252 - 42,9 * 3

252 - 128,7

123,3

k cho mk nha

x = 20 thì phải

1/5=4/20

mà 4/20=4/x

suy ra x=20

1/5 = 1x 4 / 5 x 4 = 4/20

Vậy x = 20

5(x+35)=515

x+35=515:5

x+35=103

x=103-35=68

5 (x + 35) = 515

     x + 35  = 515 : 5

     x + 35  = 103

     x           = 103 - 35

     x           = 68

5(x+35)=515 có ai biết thì trả lời giùm mình nhé nhanh lên nha

5 (x + 35) = 515

     x + 35  = 515 : 5

     x + 35  = 103

     x           = 103 - 35

     x           = 68

B=1x3/2x2x2x4/3x3x3x5/4x4x...x10x12/11x11

B=1x3x2x4x3x5x...x10x12/2x2x3x3x4x4x...x11x11

B=(1x2x3x...x10)x(2x3x5x...x12)/(2x3x4x...x11)x(2x3x4x...x11)

B=1x12/11x2

B=12/22

B=6/11

Vậy B = 6/11

Đặt thừa số chung x.

Ta có:

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+9\right)\Leftrightarrow x+\left(1+2+3+...+9\right)=135\)

\(\Leftrightarrow x+\left(1+2+3+4+5+6+7+8+9\right)\Leftrightarrow x+45=135\)

\(\Rightarrow x=135-45=90\)

Đs:

 x * 10 + (1 + 2 + 3 ... +9) = 135

 x *10 + 45                      =135

 x * 10                             = 135 - 45

 x * 10                             = 90

 x                                    =90 : 10

 x                                    = 9

Vậy x = 9

thử lại:(tự làm)

(x+x+x+...+x)+(1+2+3+....+9)=135

   9 c/s x

=x9+[(9+1)X9:2]=135

=x9+45=135

=x9=135-45

 x9=90

x=90:9

x=10

5x-10=50

5x=60

x=60:5

5(x - 2) = 50

=> x - 2 = 10

=> x = 12

vậy_

x-2 = 50 : 5

x-2 = 10

x    = 10 + 2

x    = 12

a/ tat ca la so doi nen bang 0

b/ tat ca la so doi chi co -15 la khong nen bang -15

c/ minh khong biet hinh nhu de thieu

cảm ơn Toàn nha

x= 92

x = 165

x = 21

ok k cho mik nha

x =92

x=165

x=21

x-29=63

   x=63+29=92

x-72=93

     x=93+72=165

x+54=75

     x=75-54=21