Question

x/3 - 4/y=1/5

Answer 1

THAM KHẢO

 

a,x/3 −4/y = 1/5 

4/y = x/3 −1/5 

4/y = 5x−3/15 

=> (5x - 3)y = 15.4 = 60

=> 5x-3 ; y ∈Ư(60) 

Mà 5x - 3 chia 5 thiếu 3 (dư 2) nên 5x - 3 ∈{-3;2;12}

=> y ∈ {-20;30;5}

Lặp bảng

Vậy các cặp (x;y) là (0;-20); (1;30); (3;5)

Answer 2

\(\dfrac{x}{3}-\dfrac{4}{y}=\dfrac{1}{5}\)

\(\dfrac{x}{3}=\dfrac{1}{5}+\dfrac{4}{y}\)

\(\dfrac{x}{3}=\dfrac{y+20}{5y}\)

\(x=\dfrac{3y+60}{5y}\)