Question

[Trà My]

Tìm số tự nhiên x,y sao cho :

a) (2x - 1) . (y - 3) = 10

b) (3x - 2) . (2y - 3) = 1

c) (x + 1) . (2y - 1) = 12

d) x + 6 = y(x - 1)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\Leftrightarrow\left(2x-1;y-3\right)\in\left\{\left(1;10\right);\left(5;2\right);\left(-1;-10\right);\left(-5;-2\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(1;13\right);\left(3;5\right)\right\}\)

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

hay \(\left(x,y\right)\in\left(1;2\right)\)

c: \(\Leftrightarrow\left(x+1,2y-1\right)\in\left\{\left(12;1\right);\left(4;3\right);\left(-12;-1\right);\left(-4;-3\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(11;1\right);\left(3;2\right)\right\}\)