Find the values of k for which the quadratic equation 2x^2+5x+k=0 has no real roots.
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Answered by
15
2x²+5x+k=0
25-8k<0
k>25/8
Answered by
68
given 2x²+5x+k =0
compare this with ax²+bx +c =0
a= 2, b=5, c= k
given equation doesn't has real roots
∴ discriminant < 0
b²-4ac<0
5²-4*2*k<0
25-8k<0
-8k<-25
8k>25
k>25/8
compare this with ax²+bx +c =0
a= 2, b=5, c= k
given equation doesn't has real roots
∴ discriminant < 0
b²-4ac<0
5²-4*2*k<0
25-8k<0
-8k<-25
8k>25
k>25/8
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