Answer: \((x, y) = (3, -3)\)
Ordered pairs for \(x + y = 0\):
| \(x\) | \(0\) | \(1\) | \(3\) |
| \(y\) | \(0\) | \(-1\) | \(-3\) |
| \((x, y)\) | \((0, 0)\) | \((1, -1)\) | \((3, -3)\) |
Ordered pairs for \(2x - y = 9\):
| \(x\) | \(0\) | \(4\) | \(3\) |
| \(y\) | \(-9\) | \(-1\) | \(-3\) |
| \((x, y)\) | \((0, -9)\) | \((4, -1)\) | \((3, -3)\) |
Plot both sets of points on the same graph paper (scale: 1 cm = 1 unit on both axes) and join each set to get two straight lines. The lines intersect at \((3, -3)\).
Check: \(1(3) + 1(-3) = 0\) and \(2(3) + (-1)(-3) = 9\) – both true.