Intermediate Algebra (6th Edition)

The general form of an exponential equation is $y=a*b^{x-h}+k$ with a horizontal asymptote at $y=h$. A horizontal asymptote is a line that a graph approaches, but doesn't usually cross, The horizontal asymptote for $y=2^{x}$ is the line $y=0$. Therefore this graph never touches the x-intercept.