Question icon
Grade 11Algebra

find the integer k for which the inequality x^2 – 2(4k-1)x + 15k^2 – 2k – 7 > 0 is valid for any x

Profile image of Gaurang Kotasthane
10 Years agoGrade 11
Answers icon

1 Answer

Profile image of Ajay
10 Years ago
The inequality will be greater than zero if D is less than zero
4(4k-1)2 – 4(15k2 – 2k – 7)  less than zero
Simplifying this we get
K2-6k+8 less than zero
(k-4)(k-2) less than zero
 K lies in (2, 4)