1. The equations y = 3x + 6 and y = -13x - 4 form a system of two linear equations. Since the slopes of the two equations (3 and -13) are not equal, the system has one unique solution.
2. The equations x - 2y = 63x - 6 and y = 18 form a system of two linear equations. Substituting y = 18 into the first equation, we get x - 2(18) = 63x - 6, which simplifies to x - 36 = 63x - 6. Rearranging the terms, 0x - 62x = 6 - 36, or -62x = -30. Solving for x, we get x = 30/62 = 15/31. Substituting this value of x into y = 18, we find y = 18. Therefore, the system has one unique solution.
3. The equations y = 23x - 1 and y = 23x - 2 form a system of two linear equations. Since the slopes of the two equations are equal (both 23), the lines are parallel and will never intersect. Therefore, the system has no solution.