Question

check whether x=-1 , 3 are zeroes of polynomial p(x) = (x+1) ( x-3)​

Answer 1

Putting value of x = -1

( -1 + 1)( -1 -3)

0(-4) = 0

Putting value of x = 3

( 3 + 1)(3 - 3)

4(0) = 0

since for both the values the value of the polynomial resolves to zero... both -1 and 3 are zeroes.

there you go :)