let f(x)=x^2

1. show that the line tangent to the graph of f at the point (1,1)is y=2x-1

The slope of the f(x) curve at x = 1 is

f'(x) @ x = 1 = 2

Now fond the constant b such that y = 2x + b = 1 at x = 1.
1 = 2 + b
b = -1