Question

Can someone help me with this:
A function y=f(x) and an x-value xsub0 are given.
a) Find a formula for the slope of the tangent line to the graph of f at a general point x=xsub0.
b) Use the formula obtained in part (a) to find the slope of the tangent line for the given value of xsub0.
1) f(x)=x^2-1; xsub0= -1
and
2) f(x)=x^2+3x+2; xsub0=2