Answer:
4x^2−12x+9
Step-by-step explanation:
The form of a perfect square trinomial is ...
(a +b)² = a² +2ab +b²
The first and last terms must be positive and perfect squares. The middle term must be twice the product of their roots (possibly with a minus sign).
x^2 -10x -25 . . . . -25 is not a positive perfect square
4x^2 -12x +9 . . . . 12x = 2√(4x^2·9) = 2·6x . . . . perfect square
9x^2 +12x +16 . . . 12x ≠ 2√(9x^2·16) = 2·12x
16x^2 +16x +1 . . . 16x ≠ 2√(16x^2·1) = 2·4x
