Question

If one of the zeroes of a quadratic polynomial f(x) = 14x2-42k2x-9 is negative of other. Find the value of k

Answer 1

Answer:

Given :-

• One zeros is negative of other

Let the Zeros be a

and ( - a )

f ( x ) = 14x² - 42k² x - 9

As we know

sum \: of \: zeros \: = \frac{coefficient \: of \: x}{coefficient \: of \: {x}^{2} }sumofzeros=

coefficientofx

2

coefficientofx

a \: + ( - a) = \frac{42 {k}^{2} }{14}a+(−a)=

14

42k

2

0 = {3 {k}^{2} }0=3k

2

0/3 = k²

0 = k

So , k will equal to 0

•Verification

When we put value of k and after factorising we will get one zeros negative of other

=> 14x² - 42k² x - 9 = 0

14x² - 9 = 0

( √14 x )² - ( 3 )² = 0

By using identity

[ a² - b² = ( a + b ) ( a - b ) ]

So,

( √14x + 3 ) ( √14x - 3 ) = 0

* ( √14x + 3 ) = 0

x = -3/√14

* ( √14x - 3 ) = 0

x = 3/√14

Hence we get one zeros negative of other!!

Answer 2

Answer:

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