Question

Tìm x,y thuộc Z, sao cho

  (2x-1) . y + 2x = 19 

Answer 1

=>2xy-y+2x=19

=>2x(y+1)-y-1=18

=>(y+1)(2x-1)=18

mà x,y là số nguyên

nên \(\left(2x-1;y+1\right)\in\left\{\left(1;18\right);\left(-1;-18\right);\left(3;6\right);\left(-3;-6\right);\left(9;2\right);\left(-9;-2\right)\right\}\)

=>\(\left(x,y\right)\in\left\{\left(1;17\right);\left(0;-19\right);\left(2;5\right);\left(-1;-7\right);\left(5;1\right);\left(-4;-3\right)\right\}\)