For the function f and value of a, use the magic formula to find the tangent line to f at a. We will need to calculate derivatives from scratch.
Since a = 1, f(a)= f(1) = 1.
We need to find f'(1):
We put this all into the formula
to findy = 1 + (-2)(x - 1)which can be simplified toy = -2x + 3.