What is the sum of all numbers a for which the graph of y=x^2+a and the graph of y=ax intersect one time?
y = x^2 + a
y = ax
Set the y's equal
x^2 + a = ax
x^2 - ax + a = 0
If we only have one solution, the discrminant must = 0
So
a^2 - 4a = 0 factor
a ( a - 4) = 0
The solutions are a = 0 or a = 4
So....the sum of all possible a's = 4
I actually was working on this problem while you were, I also figured it out!!!
+296 
