Question

Tìm a,b là số nguyên sao cho: (a - 3)b - a = 5

Answer 1

=>ab-3b-a=5

=>a(b-1)-3b+3=8

=>(a-3)(b-1)=8

=>\(\left(a-3;b-1\right)\in\left\{\left(1;8\right);\left(2;4\right);\left(4;2\right);\left(8;1\right);\left(-1;-8\right);\left(-2;-4\right);\left(-4;-2\right);\left(-8;-1\right)\right\}\)

=>\(\left(a,b\right)\in\left\{\left(4;9\right);\left(5;5\right);\left(7;3\right);\left(9;2\right);\left(2;-7\right);\left(1;-3\right);\left(-1;-1\right);\left(-5;0\right)\right\}\)