You may invent a value for x, substitute that value into the given equation and thereby calculate y:
If 7x - 4y = -5 and x = 0, then -4y = -5 and y = 5/4. The corresponding ordered pair is (0, 5/4). Other x values may be chosen at random and the same operations performed so as to find other possible ordered pairs corresponding to 7x -4y = 5.
