Questions on Algebra: Functions, Domain, NOT graphing answered by real tutors!

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Question 167267: If the graph of the parabola y=kx^2+6x+k+8 is tangent to x-axis, then what is the positive value of k?: If the graph of the parabola y=kx^2+6x+k+8 is tangent to x-axis, then what is the positive value of k?
Answer by oscargut(682) About Me  (Show Source):
You can put this solution on YOUR website!
if the graph is tangent to x-axis then discriminant is 0
then b^2-4ac=0
then
6^2-4(k)(k+8)=0
36-4k^2-32k=0
-4k^2-32k+36=0
k^2+8x-9=0
then k=1 or k=-9
then k=1 (positive value)
Answer: k=1