Question

Which expressions are perfect square trinomials? Check all that apply.

A. x2 + 16x + 8
B. x2 + 14x + 49
C. x2 – 5x + 25
D. x2 – 24x + 144
E. x2 + 9x – 81

Answer 1

A. Doesn't work
B. (x + 7)(x + 7) = Works
C. Doesn't work
D. (x - 12)(x - 12) = Works
E. Doesn't work

Therefore the answers are B and D
The other don't work because they do not become perfect squares.

Answer 2

perfect square trinomials are in the form
ax^2+bx+c such that
a=1
(b/2)^2=c

check each
all of them have 1 in front so skipt that step

A. (16/2)^2=8? false so no
B. (14/2)^2=49? true, this is
C. (-5/2)^2=25? false, this is not
D. (-24/2)^2=144? true, this is
E. (-9/2)^2=-81? false (easy way is that x^2 is never equal to a negative unless it is complex

B and D are answers