From the condition:

The major axis (connecting foci) is the horizontal line y = 0, coinciding with x-axis.

The center of the ellipse is the midpoint between the foci, i.e. (2,0).

The focal distance is 2c = 4 - 0 = 4;  Hence, the distance from the center to each focus is c =  = 2.


Since the major axis length is 6, the major seni-axis is  = 3.


Then the minor semi-axis is   =  =  = 5.


Thus the standard form of the ellipse equation is

 +  = 1.