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Question
For what value of k, the equation `kx^2-6x2=0` has real roots?
(a) `k≤-9/2` (b)`k≥-9/2`
(c)` k≤-2` (d) None of these
Solution
(b) `k≥-9/2`
It is given that the roots of the equation `(kx^2-6x-2=0)` are real
∴` D≥0`
⇒`(b^2-4ac)≥0`
⇒`(-6)^2-4xxkxx(-2)≥0`
⇒`36+8k≥0`
⇒`k≥-36/8`
⇒`k≥-9/2`
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