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222-9+11+12:2*14+14 = ? ( )

## Toán Lớp 6: Tìm số nguyên x,y : a)xy-x-2y=5 b)xy-2x+y=7 Can you help me ! Nhanh nhoa !

Toán Lớp 6: Tìm số nguyên x,y :
a)xy-x-2y=5
b)xy-2x+y=7
Can you help me ! Nhanh nhoa !

1. gửi bạn

2. Giải đáp + Lời giải và giải thích chi tiết:
a)xy – x – 2y = 5
(1xy – 1x) – (2y – 2) = 3
x(y – 1) – 2(y – 1) = 3
(x – 2)(y – 1) = 3
=> (x – 2) ; (y – 1) in Ư(3) = {+-1 ; +-3}
ta có bảng sau :
\begin{array}{|c|c|c|}\hline \text{x – 2}&\text{1}&\text{-1}&\text{3}&\text{-3}\\\hline \text{y-1}&\text{3}&\text{-3}&\text{1}&\text{-1}\\\hline \text{x}&\text{3}&\text{1}&\text{5}&\text{-1}\\\hline \text{y}&\text{4}&\text{-2}&\text{2}&\text{0}\\\hline\end{array}
Vậy ……….
b) xy – 2x + y = 7
(1xy – 2x) + (y – 2) = 5
x(y – 2) + 1(y – 2) = 5
(x + 1)(y – 2) = 5
=> (x + 1) ; (y – 2) in Ư(5) = {+-1 ; +-5}
\begin{array}{|c|c|c|}\hline \text{x + 1}&\text{1}&\text{-1}&\text{5}&\text{-5}\\\hline \text{y-2}&\text{5}&\text{-5}&\text{1}&\text{-1}\\\hline \text{x}&\text{0}&\text{-2}&\text{4}&\text{-6}\\\hline \text{y}&\text{7}&\text{-3}&\text{3}&\text{1}\\\hline\end{array}
Vậy ……..