Since the major axis is on the x-axis, the equation of the ellipse will be of the form,
x2a+y2b2=1...(1)
Where a is the semi-major axis.
The ellipse passes through points (4,3) and (6,2). Hence,
16a2+9b2=1...(2)
36a2+4b2=1...(3)
On solving equations (2) and (3) we obtain a2=52andb2=13
Thus the equation of the ellipse is x252+y213=1 or x2+4y2=52