The given equation, y = -3 is the equation of a horizontal line (y = b) with a slope of zero. The attached screenshot shows the graph of the given equation.
The x-intercept is the point on the graph where the line crosses the x-axis, with coordinates of (a, 0).
Linear equations involving horizontal lines always have the same y-coordinate regardless of its corresponding x-coordinate.
Hence, the given equation, y = -3 has the same y-coordinate of -3. Since it represents a horizontal line at y = -3, it is below the x-axis. This means that it will never cross the x -axis (please see the attached screenshot for your reference).
Therefore, y = -3 has no x-intercept.