Linear Quadratic Answers

Quadratic Equation : CAT 2007 Preparation Questions

Question 4 the day : April 15, 2003
The question for the day is from the topic Algebra. It is about finding a root of a quadratic, given the equation and another root.

Question
If one of the roots of the quadratic equation 2x² - 7x + q = 0 is 3, find the other root

(1) -3
(2) -1/2
(3) 1/2
(4) 1/4

Correct Choice is (3) and Correct Answer is 1/2

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Explanatory Answer

Substituting x = 3 in the given equation we get
2(3²) - 7 (3) + q = 0. Therefore, q = 3

Now, the given equation becomes 2x² - 7x + 3 = 0

By solving this we get (x - 3) (2x - 1) = 0
i.e., x = 3 & 1/2. The second root is 1/2.