Determine whether these sets S are bounded, and determine sup(S) and inf(S)
For each set S below, determine whether S is bounded, and determine sup(S) and inf(S), if they exist.
a) S = {x: x^2 < 5x}
b) S = {x: 2x^2 < x^3 + x}
c) S = {x: 4x^2 > x^3 + x}