Answers

2014-05-13T18:23:46+05:30
α and β are the zeroes 
f(x)=2x²+5x+k
α²+β²+αβ=21÷4
α²+β²+αβ=(α+β)²-αβ
α+β= -b/a = -5/2
αβ=c/a = k/2
α²+β²+αβ=(-5/2)²-k/2
              =25/4-k/2
α²+β²+αβ=21/4
21/4=25/4-k/2
21/4-25/4=k/2
-4/4=k/2
-1=k/2
k=-1×2
k=-2
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2014-05-13T18:38:13+05:30
The answer is k=2 and that is so true

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