SOLUTION: Find the value(s) of k so that 3/4 x^2 + kx = -27 has one real rational root.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the value(s) of k so that 3/4 x^2 + kx = -27 has one real rational root.      Log On


   

Question 328671: Find the value(s) of k so that 3/4 x^2 + kx = -27 has one real rational root.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Use the discriminant, D.
D=b%5E2-4ac
When D=0, the quadratic has one real rational (double) root.
%283%2F4%29x%5E2%2Bkx%2B27=0
D=k%5E2-4%283%2F4%29%2827%29=0
k%5E2-81=0
k=0+%2B-+9
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Both instances of k are shown in the graph (+9-Red,-9 Green).
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