Question

Which of the following does not factor as a perfect square trinomial?
A.
16a^2-72a+81
B.
169x^2+26xy+y^2
C.
x^2-18x-81
D.
4x^2+4x+1

Answer 1

C

Answer 2

100% sure

Answer 3

\[a^2+2*a*b+b^2=\left( a+b \right)^2\]
\[a^2-2*a*b+b^2=\left( a-b \right)^2 \]

Answer 4

thanks