Answer
a) It means in that point of intersection, if you draw the tangent line of each curve, they will imtersect at right angle.
b) the answer is the demonstration in the "work step by step" section, but they intersect at right angles at least at one point, $x=1$.
Work Step by Step
a) There is no sense in saying the angle formed by points of intersection, or curves, because you need lines to form angles. The obvious choice of line is the tangent line, which best describes the behavior of the curve at that point.
b) As we know from item (a) we need the slopes of tangent lines, so we derivate the functions to get them. When two lines intersect at right angle, the product of their slope must be equal to $-1$. Doing so, we get to an equation of 4th order, which we don't need to know all the solutions, we just need to find one to show there exists such an intersection, and it's easy to see that $x=1$ solves that equation. All that is done on the image below.
