The line y = 2x + c is tangent to the parabola y^2 = 8x. Then find the value of c.
I found out that this website has your question and a pretty good answer: https://socratic.org/questions/find-the-value-of-the-constant-c-for-which-the-line-y-2x-c-is-a-tangent-to-the-c
Hope this helps!!!