Question

tìm các số tự nhiên x,y sao cho:

a) (x+5)⋮(x+2)
b) (x+1).(y-2)=6

Answer 1

a: =>x+2+3 chia hết cho x+2

=>\(x+2\in\left\{1;-1;3;-3\right\}\)

hay \(x\in\left\{-1;-3;1;-5\right\}\)

b: \(\Leftrightarrow\left(x+1;y-2\right)\in\left\{\left(1;6\right);\left(6;1\right);\left(2;3\right);\left(3;2\right);\left(-1;-6\right);\left(-6;-1\right);\left(-2;-3\right);\left(-3;-2\right)\right\}\)

hay \(\left(x,y\right)\in\left\{\left(0;8\right);\left(5;3\right);\left(1;5\right);\left(2;4\right);\left(0;-4\right);\left(-7;1\right);\left(-3;-1\right);\left(-4;0\right)\right\}\)