sine function transforms

hello

say i have two functions, $y=3^x$ and $y=x+1.2$ and i wanted to find where they intersect. since $y=x+1.2$ is a line, if i could rotate both functions so that $y=x+1.2$ became the x-axis, $y=0$ , then to find the intersection i would solve the now rotated $y=3^x$ by setting $y=0$ , then un-rotating the solutions.

firstly, how can i accomplish this rotation transform, and secondly, can i do more complex transforms, like $y=2^x$ and $y=x^2$ transformed so that $y=x^2$ becomes the x-axis? again, i would also have to de-transform the solutions. if i was at all fluent in calculus (took 4 semesters worth of it, haha, just don't remember much), then i'm sure i'd have a better idea on how to figure this out, or at least ask better questions.

*edit*
for this one, i visualize flattening out one curve, and the other one obeys the same movements. mathematically i think it would be taking lines perpindicular to $x^2$ and rotating each one into $y=0$ as in the first case.

and for the real kicker (or maybe you'll just kick me), how about $y=sin(\pi*2^x)$ and $y=sin(\pi*2^{1-x})$ ? ..and again, de-transformation.

*edit*
transforming certain functions would cause the other to no longer be a function..not a good idea haha.
but,
given the range $0<x<1$ could these last functions be modeled by a polynomial?

thanks for any help or ideas!