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

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

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.