Question

Suppose the function f of x = 4/x
a) Use the definition of the derivative to show that f ' (-2) = -1.
b) Write an equation for the line tangent to the graph of f at x = -2.
So for a i did
f'(x)= 4/x^-2
4/-(2)^2
4/-4
-1
but how would i do b???