Question

Tìm số nguyên x,y sao cho (x+2).(y-1)=3

(3-x).(xy+5)=-1

Answer 1

\(\left(x+2\right)\left(y-1\right)=3\)

\(\Leftrightarrow\left(x+2;y-1\right)\in\left\{\left(1;3\right);\left(3;1\right);\left(-1;-3\right);\left(-3;-1\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(-1;4\right);\left(1;2\right);\left(-3;-2\right);\left(-5;0\right)\right\}\)

\(\left(3-x\right)\left(xy+5\right)=-1\)

\(\Leftrightarrow\left(3-x;xy+5\right)\in\left\{\left(1;-1\right);\left(-1;1\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(2;-3\right);\left(4;-1\right)\right\}\)