SOLUTION: Find the value of alpha such that the quardratic equation(alpha-3)x square+(alpha-3)x+4=0,has equal roots? The given answer is '4'but I don't know to solve it...

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Question 389016: Find the value of alpha such that the quardratic equation(alpha-3)x square+(alpha-3)x+4=0,has equal roots?

The given answer is '4'but I don't know to solve it...
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
%28alpha-3%29x%5E2+%2B+%28alpha+-+3%29x+%2B+4+=+0;
The discriminant has to be equal to 0 for the roots to be equal. Then alpha+=+3 or alpha+=+19. But alpha+=+3 won't result in a quadratic equation, so alpha+=+19.