We plot those two points



The parabola's axis of symmetry is a vertical line thgrough the vertex,
so we draw in the axis of symmetry (in green)







Now we sketch the parabola



We can see by the symmetry of a parabola that the other x-intercept
must be the same distance on the right of -4 (since that's the 
x-coordinate of the vertex), as (-11,0) is to the left of -4.  Since
-11 is 7 units to the left of -4, the x-intercept must be 7 units to
the right of -4 on the x-axis.  And -4+7 = 3.  So the other x-intercept
is (3,0),

Edwin