Question 160346
The graph of function y= x^2 - kx + k + 8 touches the x-axis at one point. What 
is the value of k? 
------------------------------
A quadratic has one solution when the discrimanant is zero.
-----------------
Your quadratic has a = 1, b = -k,c = k+8
---------
Discrimant equation:
b^2 - 4ac = 0
(-k)^2-4*1*(k+8) = 0
k^2 -4k -32 = 0
k^2-8k+4k-32 = 0
k(k-8)+4(k-8) = 0
(k-8)(k+4) = 0
k = 8 or k = -4
==============================
Cheers,
Stan H.