ANSWER: C because of how the multiples of 25 are 5 and 5 and the multiples of 16 can be -4,-4... 5*-4+5*-4=-40 (5x-4)²= ((5²)x²-40x+(-4²))=25x²-40+16
C //Brief explanation Using a discriminant (b^2 - 4ac), for a perfect square the discriminant = 0. For A the discriminant is >0 (1620) For B the discriminant is >0 (1568) For C the discriminant = 0 For D the discriminant is < 0 (-108)
