Question

If 3 is zero of the polynomial xsquare+2x-a . find the value of a .​

Answer 1

Answer:

3 is the zero of the polynomial, then f(3) = 0

f(3) = 0

(3²)+2(3)-a= 0

9 + 6 - a= 0

15 - a = 0 .

15 = a.

Now, The polynomial is x² + 2x - 15 .

Factorising the polynomial,

x² + 2x - 15

x² + 5x - 3x - 15

x ( x + 5 ) - 3 ( x + 5 )

( x + 5 ) ( x - 3 )

Therefore , x²+2x-15 = (x+5)(x-3)

Zero of the polynomial : The value of the variable for which polynomial is 0

( x + 5 ) ( x - 3 ) = 0

x = -5 , x = 3 .

Therefore, the other zero is -5 .

Answer 2

Step-by-step explanation:

x²+2x-a=0

(3)²+2(3)-a=0

9+6-a=0

a=9+6

a=15