Question 1017092
Find all k so that the graph of y = -1/4x^2 +kx  -9 is tangent to the x-axis.
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If you mean -(1/4)x^2 +kx  -9
--> Discriminant = 0
k^2 - 9 = 0
k = -3, +3
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PS  -x^2/4 +kx  -9 is a better entry.