Somehow I seem to be having the hardest time in what should be the easiest part. Could someone help me find the domain of these two functions?

1) h = 64 - pi*L / 2

2) 16 = 2x^2*h

I got an answer for this one, is it (0, +infinity)?

3) 1200 = x^2 + 4xh

Any help is appreciated!