SOLUTION: for what values of k will the function f(x)=x^2 +6x+k a) cut the a-axis twice b) touch the x-axis c) have no x- intercepts

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Question 422025: for what values of k will the function f(x)=x^2 +6x+k
a) cut the a-axis twice
b) touch the x-axis
c) have no x- intercepts

Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!

Hi
Using the vertex form of a parabola, where(h,k) is the vertex
for what values of k will the function f(x)=x^2 +6x+k
f(x)=x^2 +6x+k = (x+3)^2 -9 +k |completing the square
Note parabola opens upward(coefficient of the squared term >0)
a) cut the a-axis twice (-9+k)<0 or k < 9 Vertex below the x-axis
b) touch the x-axis (-9+k) = 0 or k = 9
c) have no x- intercepts (-9+k)> 0 or k > 9 Vertex above the x-axis



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