Question

Check whether (x+3) is the factor of p(x) = x^2-9

Answer 1

If p(x) is divided by (x+3), then the remainder = p(-3)
p(x) = x²-9
p(-3) = (-3)²-9
= 9-9
= 0
(x+3) is a factor of p(x) as remainder is 0.

Answer 2

Hi there !!

p(x) = x² - 9

x + 3 = 0

x = -3

if x+3 is a factor of p(x) , 
then :-

p(-3) must be equal to 0

p(-3) = [-3]²  - 9 
        = 9 - 9
        = 0

Here ,
p(-3) = 0

Hence ,

(x+3) is a factor of p(x)