Question

What is the equation of the tangent line to `f(x)=3-14x` at `x=8`?

Answer 1

Your `f(x)` is a linear function whose graph is a straight line, so I am not sure whether or not you can find a tangent line to a...line (a tangent line being a line with only one point in common with your curve)! You may argue that a line crossing your line at `x=8` (having a point in common) has the same property of the tangent but I think that it doesn't work (also because you'll get an `oo` number of them).