Question

if r1,r2,r3 are root of polynomial 7x³+21x²7x³+21x²-4x+6 then​

Answer 1

Answer:

Correct option is

C

19

We know that A.M≥G.M

4

2

r

1

+

4

r

2

+

5

r

3

+

8

r

4

≥(

2

r

1

4

r

2

5

r

3

8

r

4

)

4

1

We know from the given equation that (r

1

r

2

r

3

r

4

)=

4

5

Substituting we get.

G.M.=(

64⋅(4)

1

)

4

1

=

4

1

Hence, A.M=G.M(∵

2

r

1

+

4

r

2

+

5

r

3

+

8

r

4

=1)

∴ The numbers will be equal.

2

r

1

=

4

r

2

=

5

r

3

=

8

r

4

=

4

1

Hence,

r

1

=

2

1

,r

2

=1,r

3

=

4

5

,r

4

=2→(1)

From the equation given , we get sum of the roots as

r

1

+r

2

+r

3

+r

4

=

4

a

→(2)

From (1) and (2), we get

4

19

=

4

a

⇒a=19

Step-by-step explanation:

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Answer 2

Answer:

if r1,r2,r3 are root of polynomial 7x³+21x²7x³+21x²-4x+6 then