SOLUTION: The equation x^2-9x+2k=0 has roots a and b.If a = 2b,find the value of k Thanks~~

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Question 457992: The equation x^2-9x+2k=0 has roots a and b.If a = 2b,find the value of k
Thanks~~
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
If b is one root, then 2b is the other. Then from algebra, b*(2b) = 2k, or b%5E2+=+k. Also the sum of the roots must be equal to the negative of -9/1 = -9, or b+2b = -(-9) = 9, or 3b = 9, or b = 3. This is one root. The other root is 2*3 = 6. k+=+b%5E2+=+3%5E2+=+9.