Question

Answer 1

xy+3x+3y=-16

(xy+3y)+3x=-16

y(x+3)+3x+9=-16+9

y(x+3)+3(x+3)=-7

(x+3)(y+3)=-7

Answer 2

Ta có : xy + 3x + 3y = -16

=> x(y + 3) + 3y = -16

=> x(y + 3) + (3y + 9) = -16 + 9

=> x(y + 3) + 3(y + 3) = -7

=> (x + 3)(y + 3) = -7

=> x + 3;y + 3 ∈ Ư(-7) ∈ {-7;-1;1;7}

=> (x + 3;y + 3) ∈ {(-7;1);(1;-7);(7;-1)(-1;7)}

=> (x;y) ∈ {(-10;-2);(-2;-10);(4;-4);(-4;4)