Question

show that 2 is not zero of the polynomial xcube-13xsqure + 54x - 72

Answer 1

$if \: 2 \: is \: the \: zero \: of \: polynomial \: p(x) \: then \: p(2) = 0 \\ so \: p(x) = {x}^{3} - 13 {x}^{2} + 54x - 72 \\ p(2) = 8 - 52 + 108 - 72 \\ = - 8(not = 0) \\ thus \: 2 \: is \: not \: the \: zero \: of \: p(x)$

Answer 2

p(x)=x³-13x²+54x-72
Let us substitute x=2
p(2)=(2)³-13(2)²+54(2)-72
      =8-52+108-72
      =-8
as the remainder is not 0.In the given p(x) 2 is not a zero

:) Hope this helps!!!!!!!!!