The graph of that is gotten by plotting

(-2,19), (-1,3), (0,1), (1,1), (2,15) 



The slope of a tangent line at a point IS the derivative
at that point.  So we find 



Evaluate that at x=1



Now we find the equation of the line with slope m=3 that
goes through to point where x=1.  We must find the y-coordinate,
by substituting x=1 in the original equation for the graph:





Use the point-slope formula:

y - y1 = m(x - x1)
where (x1,y1) = (1,1)

y-1 = 3(x-1)
y-1 = 3x-3
  y = 3x-2    <---answer

Find the points on that tangent line (0,-2), (1,1), (2,4), (3,7)
and graph it as a check to make sure it looks like it's tangent 
to the curve:




Edwin