Question

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Answer 1

Answer:

Let p(x)=x

2

+2x−a

As the zero of this polynomial is 3, we know that p(3)=0.

x

2

+2x−a=0

Put x=3, we get

(3)

2

+2(3)−a=0

⇒9+6−a=0

⇒15−a=0

⇒−a=−15

⇒a=15

Answer 2

AnsWer :

B )

QuestioN :

If 3 is a zero of a polynomial x² + 2x - a, then value of a.

A ) 1 / 15.

B ) 15.

C ) - 15.

D ) - 1 / 15.

SolutioN :

We have, Polynomial.

$\tt \dagger \: \: \: \: \: {x}^{2} + 2x - a$

Compare With general expression.

$\tt \dagger \: \: \: \: \: a' {x}^{2} + b'x + c.$

Where as,

• a' = 1.
• b' = 2.
• c' = a.

__________________

• p( x ) = 0.
• p( 3 ) = 0

Putting the value of a = 3.

$\tt : \implies \: \: \: \: \: {x}^{2} + 2x - a$

$\tt : \implies \: \: \: \: \: {(3)}^{2} + 2(3)- a = 0.$

$\tt : \implies \: \: \: \: \: 9 + 6- a = 0.$

$\tt : \implies \: \: \: \: \: 15- a = 0.$

$\tt : \implies \: \: \: \: \: - a = - 15.$

$\tt : \implies \: \: \: \: \: a = 15.$

Therefore, the value of a is 15.