If the two curves and (where k is a constant) have exactly one point in common, what much be the value of k?
If I had to guess at an answer, I'd say it's because they don't cross each other, if they could cross each other they could clearly touch the same point with different tangent lines. But, thats just a guess.
Also, how would you solve for x at this point? I can see that the point would be But I don't know how to solve for it without just being able to "see" the answer.