Answer:
The error is in computing the y intercept. It should be at (0, -6) not (0, 6)
Explanation:
The equation of the line is
y intercept is at point x = 0
When x = 0,
So y intercept is at point (0, -6)
If we plot a second point 3 units down and 4 units right we should get the point 0 + 4, -6 - 3) = (4, -9)
Plugging this into the original correct equation satisfies the equation
So we can see that the line does pass through (4, -9)
See attached graph for further clarification