SOLUTION: One root of x^2-4x+4a=0 is 2-4i. What is the value of a ?
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Question 119662: One root of x^2-4x+4a=0 is 2-4i. What is the value of a ?
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
If 2-4i is a root, then when , the entire left side will equal zero.
Start with the given equation
Plug in
Foil and distribute
Replace with
Multiply
Combine like terms
Add 20 to both sides
Combine like terms on the right side
Divide both sides by 4 to isolate a
Divide
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Answer:
So our answer is
Note: you can check this answer by using the quadratic formula
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