Answers

2016-04-23T16:07:27+05:30
X²+7x+7=0
x= -b+ or - √b²-4ac/2a
x=-7 + or - √7²-4×7/2
x= -7 + or - √49-28/2
x= -7 + or - √21/2
so,
x= -7 + √21/2 (alpha)
and
x= -7 - √21/2 (beta)

note:- divided by 2 is for whole and not only for √21
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BTW :- BY the way
in which school. u r
sri chaitanya school
which school u r
i knw that method but it did nt striked
2016-04-24T12:20:46+05:30
∵α & β are roots of the given polynomial.
∴We get,
  α+β= -b/a = -7.
  αβ = c/a = 7.

 1/α + 1/β - 2αβ
= (α+β) /αβ - 2αβ
= -7/7 -2*7
= -15.(Ans)

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