Question

Which of the following is not a perfect square trinomial?
(Points : 1)
169 − 26y + y^2
81 + 18y + y^2
64 + 8y + y^2
25 + 10y + y^2

Answer 1

you have to check them with
Ax^2+Bx+C
find two factors of A*C that add up to B
here 169−26y+y^2 A*C=(1)*(169)=169, two factors of 169 that add up to -26?
(-13)*(-13)=169 and -13+(-13)=-26, so the first option is a perfect square, (y-13)^2=169 − 26y + y^2 from (a+b)^2=ax^2+2ab+b^2, with neg. sign the 2ab term is also negative

Answer 2

https://mathway.com/