c)\(\dfrac{3}{8}\times\dfrac{5}{8}+y=\dfrac{5}{4}\) 

   \(\dfrac{15}{64}+y=\dfrac{5}{4}\) 

           \(y=\dfrac{5}{4}-\dfrac{15}{64}\) 

           \(y=\dfrac{65}{64}\)

d, \(\dfrac{3}{8}+\dfrac{5}{8}\times y=\dfrac{5}{4}\) 

          \(\dfrac{5}{8}\times y=\dfrac{5}{4}-\dfrac{3}{8}\) 

          \(\dfrac{5}{8}\times y=\dfrac{7}{8}\) 

                 \(y=\dfrac{7}{8}:\dfrac{5}{8}\) 

                \(y=\dfrac{7}{5}\)

 a, 3/4 x y = 3/5 + 3/10   

3/4 x y = 9/10

y = 9/10 : 3/4

y = 6/5

b, 3/5 : y = 3/4 - 2/5

3/5 : y = 7/20

y = 3/5 : 7/20 

y = 12/7

y/8+yx8-56,78=138,22

yx(1/8+8)-56,78=138,22

yx8,125=138,22+56,78

yx8,125=195

y=195:8,125

y=24

Vậy y=24. k mk nha

y: 8 + y x 8 - 56,78 = 69,11 x 2  

yx1/8+yx8-56,78=69,11x2

yx(1/8+8)-56,78=138,22

yx8,125=138,22+56,78

yx8,125=195

y=195:8,125

y=24

y=24 nha

Câu 3: Thay x; y trong số 40xy bởi các chữ số thích hợp để số đó chia hết cho 2; 3; 4 và 5.

A.   x = 4; y = 0             B.x= 4; y = 8                C. x=8; y = 4             D. x =8; y = 0

D nha

\(y+y+\dfrac{1}{4}\times\dfrac{7}{2}+y+\dfrac{1}{8}=139\)

\(3\times y+\dfrac{7}{8}+\dfrac{1}{8}=139\)

\(3\times y+1=139\)

\(3\times y=138\)

\(y=46\)

Vậy y = 46.

`y xx1/2+y xx1/4+y xx1/8=22/24`

`=>y xx (1/2+1/4+1/8)=11/12`

`=> y xx (4/8+2/8+1/8)=11/12`

`=> y xx 7/8=11/12`

`=>y=11/12:7/8`

`=>y=11/12xx8/7`

`=>y=22/21`

`y xx 1/2 + y xx 1/4 + y xx 1/8 = 22/24`

`=> y xx (1/2 + 1/4 + 1/8) = 11/12`

`=> y xx ( 4/8 + 2/8+ 1/8) = 11/12`

`=> y xx 7/8 = 11/12`

`=> y= 11/12 : 7/8`

`=> y=11/12 xx 8/7`

`=> y=22/21`

\(\frac{4y}{3}+\frac{2y}{3}+8y=150\)

\(\frac{6y}{3}+8y=150\)

\(2y+8y=150\)

\(10y=150\)

\(y=15\)

vậy \(y=15\)

 y x (4/3+2/3+8)=150

 y x 10 = 150

 y = 150 : 10 = 15

k mk nha