Q7 If (-4) is a root of the quadratic eqn. X
2
+Px-4=0 and the equation 2X2
+P X+k=0 has equal roots. Find
the value of k.
Answers
Answered by
22
Answer:
9/8
Explanation:
- 4 is a root of x^2 + Px - 4 = 0, it means it will satisfy the given condition. So for x = - 4 equation will remain same :
⇒ ( - 4 )^2 + P( - 4 ) - 4 = 0
⇒ 16 - 4P - 4 = 0
⇒ 16 - 4 = 4P
⇒ 12 = 4P
⇒ 3 = P
2x^2 + Px + k = 0 has equal roots which means its discriminant is 0.
⇒ P^2 - 4( 2 * k ) = 0
⇒ ( 3 )^2 - 8k = 0 { P = 3 }
⇒ 9 - 8k = 0
⇒ 9 = 8k
⇒ 9/8 = k
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