To obtain the domain and the range, I will give you the graph of the section so that you can understand better.
4x^2+25y^2=100
The range:
set y=0, and solve for x:
4x^2=100
x^2=25
x=+/-5
thus the domain is:
[-5,5]
Range:
set x=0 and solve for y:
25y^2=100
y^2=4
y=+/-2
thus the range is:
[-2,2]
