Question

if 3 is a zero of the polynomial x square +2x-a find a​

Answer 1

Answer:

15

Step-by-step explanation:

Let $P(x)=x^2+2x-a$

By factor theorem, if 3 is a zero of P(x), then $(x-3)$ divides $P(x)$

$\implies P(3)=0$

$\implies 3^2+2(3)-a = 0$

$\implies 9+6-a = 0$

$\therefore a = 15$

Answer 2

Step-by-step explanation:

p(x) = x square - 2x-a

p(3) = (3) square - 2*3 - a=0

p(3) = 9 - 6 - a= 0

p(3) = 3 - a =0

p(3) = - a = - 3

p(3) = a =3

Hence a = 3

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