1. The slope of the tangent line to the graph of a function at a point x is given by the derivative of the function at that point. Thus, the optimal approach is to find the derivative of the first function, and find where it is equal to the slope of the given line.
2. This is the same, except you are now equating the derivative to the value 5 and solving for x.
Show some work and show where you are having difficulty.