Q. 8 The zeroes of the quadratic polynomial x2 + kx + k where k = 0,
(a) cannot both be positive
(b) cannot both be negative
(c) are always unequal
(d) are always equal
Plz give a detailed and simplified answer
Answers
Answered by
54
Since you didnt reposted question am explaining here
x2+kx+k,k≠0
roots or zeroes=(-k+√(k∧2-4k))/2,(-k-√(k∧2-4k))/2
since k≠0 ,roots can't be zero
the nature of root depends on √(k∧2-4k )
k<0 then √(k∧2-4k)>k so roots will be one positive and one negative
if k>0 then √(k∧2-4k) < k both roots will be negative
so both roots can't be positive
veditharv:
Plz tell detailed answer....I didn't understand it
Answered by
55
Answer:
The zeroes of this polynomial cannot be positive.
Let us try solving the quadratic by giving values to k.
If we take k as 5 and solve, we will get x as -1.38 and -3.61.
On the other hand, if we take k as 4, then we will get x as -2.
If k is taken to be negative such as -3, then the roots will be both positive and negative.
Hence option A.
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