Question 78746
The given equation is:


{{{ f(x) = x^2 - 2x - 8 }}} 


This can be written as:  



{{{f(x) = y = x^2 - 2x - 8 }}} 



{{{ y = x^2 - 2x + 1 - 1 - 8 }}} 


{{{ y = (x - 1)^1 - 9 }}}    


From this equation we observe that the equation of symmetry is x = 1 and it is a parabola facing above (or concave upwards) 


The vertex of this graph is (-9,1) and the graph of this is plotted as shown below.


{{{ graph( 400, 400, -15, 15, -15, 15, x^2 - 2x - 8) }}} 



I hope the solution is quite clear and if you have any queries you can get back to me.


Regards
Chitra