x − y = 4
−y = 4 − x
y = x − 4
при x = 2, y = 2 − 4 = −2, (2;−2);
при x = 8, y = 8 − 4 = 4, (8;4).

4x + y = 3
y = 3 − 4x
при x = 1, y = 3 − 4 * 1 = 3 − 4 = −1, (1;−1);
при x = −2, y = 3 − 4 * (−2) = 3 + 8 = 11, (−2;11).

x − 5y = 5
x = 5 + 5y = 5(1 + y)
при y = 1, x = 5(1 + 1) = 5 * 2 = 10, (10;1);
при y = −2, x = 5(1 − 2) = 5 * (−1) = −5, (−5;−2).

3x + 2y = 6
2y = 6 − 3x
y = 3 − 1,5x
при x = 4, y = 3 − 1,5 * 4 = 3 − 6 = −3, (4;−3);
при x = 0, y = 3 − 1,5 * 0 = 3 − 0 = 3, (0;3).