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Quadratic Equation - February 07, 2005
The Math Practice Question for the day is from the topic Quadratic Equation in Algebra.
Question
What is the highest integral value of 'k' for which the quadratic equation x2 - 6x + k = 0 have two real and distinct roots?
A. 9
B. 7
C. 3
D. 8
E. 12
The correct choice is (D) and the correct answer is 8.
Explanatory Answer
Any quadratic equation will have real and distinct roots if the discriminant D > 0
The discriminant of a quadratic equation ax2 + bx + c = 0 is given by b2 - 4ac
In this question, the value of D = 62 - 4*1*k
If D > 0, then 36 > 4k or k < 9.
Therefore, the highest integral value that k can take is 8.
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