Найдите все немногочисленные решения уравнения:а)(2x-y) (x+2y) = -3б)2x^2+xy-y^2 = -3

a) (2x - y)(x + 2y) = -3

1) 2x - y = 3 =gt; y = 2x - 3

x + 2y = -1 =gt; x + 2(2x - 3) = - 1 =gt;

x + 4x - 6 = -1 =gt; 5x = 5 =gt; x = 1

y = 2x - 3 = 2 - 3 = -1.

1-ое решение (x, y) = (1, -1)

2) 2x - y = - 3 =gt; y = 2x + 3

x + 2y = 1 =gt; x +2(2x + 3) = 1 =gt;

x + 4x + 6 = 1 =gt; 5x = - 5 =gt; x = -1

y = 2x + 3 = -2 + 3 = 1.

2-ое решение (x, y) = (-1, 1)

3) 2x - y = 1 =gt; y = 2x - 1

x + 2y = -3 =gt; x + 2(2x - 1) = -3 =gt;

x + 4x - 2 = -3 =gt; 5x = -1 =gt; x = - 1/5 - нецелое.

4) 2x - y = -1 =gt; y = 2x + 1

x + 2y = 3 =gt; x + 2(2x + 1) = 3 =gt;

x + 4x + 2 = 3 =gt; 5x = 1 =gt; x = 1/5 - нецелое.

Всего два решения (x, y) = (1, -1) и (x, y) = (-1, 1)

б) 2x + xy - y = -3

x - y + x + xy = -3

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

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

(x + y)(2x - y) = -3

1) x + y = 3 =gt; y = 3 - x

2x - y = -1 =gt; 2x - 3 + x = -1 =gt;

3x - 3 = -1 =gt; 3x = 2 =gt; x = 2/3 - нецелое

2) x + y = 1 =gt; y = 1 - x

2x - y = -3 =gt; 2x - 1 + x = -3 =gt;

3x -1 = -3 =gt; 3x = -2 =gt; x = -2/3 - нецелое

3) x + y = -3 =gt; y = -3 - x

2x - y = 1 =gt; 2x +3 + x = 1 =gt;

3x + 3 = 1 = 3x = -2 =gt; x = -2/3 - нецелое

4) x + y = -1 = y = -1 - x

2x - y = 3 =gt; 2x +1 + x = 3 =gt;

3x + 1 = 3 =gt; 3x = 2 =gt; x = 2/3 - нецелое.

Второе уравнение не имеет решений в целых числах.