find equation of the tangent line to the graph of f(x) at the given point f(x)=(x-1)(2x+3)/(x-5) at 9, 42
method:
expand the top, then take the derivative using the quotient rule.
Plug in the point (9,42) to get the slope
now you have the slope and a point, use the grade 9 way to find the equation of that straight line.