a,(x-1/12):23/12=7/46

x-1/12=7/46 x 23/12

x-1/12=7/24

x=7/24+1/12

x=8

b, 13/15-(13/21+x)=7/10:4/12

13/15-(13/21+x)=21/10

13/21+x=13/15-21/10

13/21+x=-37/30

x=-37/30-13/21

x=-389/210

đúng k tke bạn ơi

\(x-\frac{7}{36}=-\frac{4}{7}-x\)

\(\Rightarrow x+x=-\frac{4}{7}+\frac{7}{36}\)

\(\Rightarrow2x=-\frac{95}{252}\)

\(\Rightarrow x=-\frac{95}{252}.\frac{1}{2}=-\frac{95}{504}\)

(13x7+13x8):(29/3-y)=39

=>[13x(7+8)]:(29/3-y)=39

=>(13x15):(29/3-y)=39

=>195:(29/3-y)=39

=>29/3-y=195:39=5

=>y=29/3-5

=>y=29/3-15/3

=>y=13/3

(13 x 7 + 13 x 8) : (29/3 - y) = 39

=> [13 x (7 + 8)] : (29/3 - y) = 39

=> (13 x 15) : (29/3 - y) = 39

=>195 : (29/3 - y) = 39

=> 29/3 - y = 195 : 39 = 5

=> y = 29/3 - 5

=> y = 29/3 - 15/3

=> y = 13/3

Ta có:(13.7+13.8) : (29/3-y)=39

       [ 13.(7+8) ] : (29/3-y)=39

               13.15 : (29/3-y)=39

                            29/3-y=5

                                   y=14/3

a: =152,3+7,7+2021,19-2021,19

=160

b: =7/15*3/14*20/13

\(=\dfrac{7}{14}\cdot\dfrac{3}{15}\cdot\dfrac{20}{13}=\dfrac{1}{2}\cdot\dfrac{1}{5}\cdot\dfrac{20}{13}=\dfrac{2}{13}\)

c: \(=\dfrac{7}{4}\left(\dfrac{13}{12}-\dfrac{10}{12}\right)+\dfrac{5}{6}=\dfrac{7}{16}+\dfrac{5}{6}=\dfrac{61}{48}\)

Có:4-(27-3)=x-(13-4)

=>x-(13-4)=4-(27-3)

x-9=4-24

x-9=-20

x=-20+9

x=-11

Vậy x=-11

Đúng đấy,TICK nha!^^

kkjkjkkjj

deo biet H cho tao khong tao dien tan noi giet chet

( x+1) +(x+4 ) +(x+7) +(x+10)+.................+(x+28) =155

    x*10 +( 1+4+7+10+...+28) =155

  x*10 +145 =155

            x*10=155-145

           x*10=10

               x=10/10 

                   x=1

vay x = 1 

tk mình nhé

k minh giai cho

bang 1 nhe

tk nha

4 -(27 - 3) = x -(13 - 4)

4 - 24 = x - 9

x - 9 = -20

x=  -20 + 9 = -11

4-(27-3)=x-(913-4)

4-27+3=x-913+4

-20     =x-913+4

-20+913-4=x

889    =x

=>x=889

chỗ cuối cùng có cái dấu ) là sao thế bạn

ban vào sách chuyên đề nâng cao phát triển toán là có bài này nha