Question

tìm các số nguyên x và y thõa mãn:
a)(2x+1).(y-3)=1

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

giúp mình với mai đi học rồi

ai đúng mình tick cho

Answer 1

a: (2x+1)(y-3)=1

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

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

b: (x+1)(xy-1)=3

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

\(\Leftrightarrow\left(x,xy-1\right)\in\left\{\left(0;3\right);\left(2;1\right);\left(-1;-2\right);\left(-4;-1\right)\right\}\)

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