Question

check whether x=-1 and x=2 are zeroes of the polynomial p(x)=(x+1)(x-2)

Answer 1

p(X)=(-1+1)(2-2)
p(X)=(0)(0)
p(X)=0

Answer 2

zeros of any polynomial means
when we put the value of it in polynomial . value of polynomial must be equal to zero.
e.g., p(x') = 0 where, x' is the zeros .

P(x) = (x + 1)(x - 2)
now, put x = -1
P(-1) = (-1 + 1)(-1 - 2) = 0.(-3) = 0
P(-1) = 0 hence, x = -1 is zero of given polynomial.

again, put x = 2
p(2) = (2+1)(2 - 2)
= 3 . 0 = 0
e.g., P(2) = 0 so, x = 2 is also zero of given polynomial.