Question

HELP!!! Which of the following is not a perfect square trinomial? A. 169 – 26y + y2 B. 81 + 18y + y2 C. 64 + 8y + y2 D. 25 + 10y + y2

Answer 1

Let's review the options:
A. 169-26y+y^2 can be factorised into (13-y)(13-y)
B. 81+18y+y^2 can be factorised into (9+y)(9+y)
C. 64+8y+y^2 cannot be factorised into double brackets
D. 25+10y+y^2 can be factorised into (5+y)(5+y)

Therefore your answer is the odd one out, C.