Question

Tìm y biết: (y + 1/3) + (y + 1/9) + (y + 1/27) + (y + 1/81) = 56/81

Answer 1

4 x y + (1/3 + 1/9 + 1/27 + 1/81) = 56/81

4 x y + (27/81 + 9/81 + 3/81 + 1/81) = 56/81

4 x y + 40/81 = 56/81

4 x y  = 56/81 - 40/81 = 16/81

y = 4/81

Answer 2

\(\left(y+\frac{1}{3}\right) +\left(y+\frac{1}{9}\right)+ \left(y+\frac{1}{27}\right)+\left(y+\frac{1}{81}\right)=\frac{56}{81}\)

\(y\cdot4+\left(\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\right)=\frac{56}{81}\)

\(y\cdot4+\frac{40}{81}=\frac{56}{81}\)

\(y\cdot4=\frac{56}{81}-\frac{40}{81}\)

\(y\cdot4=\frac{16}{81}\)

     \(y=\frac{16}{81}:4\)

      \(y=\frac{4}{81}\)

Answer 3

(y+1/3)+(y+1/9)+(y+1/27)+(y+1/81)=56/81

=> y+1/3+y+1/9+y+1/27+y+1/81=56/81

=>4y+ 27/81+9/81+3/81+1/81=56/81

=> 4y+40/81=56/81

=>4y=16/81

=>y=4/81

Answer 4

ai cũng trả lời đúng nhưng mình chọn ai trả lời trước thôi

Answer 5

lấy 4 ở đâu vậy???

Answer 6

tại sao lại chia cho 4 ?

Answer 7

vì sao bằng 4/18

Answer 8

có 4y nên chia cho 4

4y = y.4

Answer 9

4 x y + (1/3 + 1/9 + 1/27 + 1/81) = 56/81

4 x y + (27/81 + 9/81 + 3/81 + 1/81) = 56/81

4 x y + 40/81 = 56/81

4 x y  = 56/81 - 40/81 = 16/81

y = 4/81