A perfect square trinomial is an expression of the form \( (a \pm b)^2 \), which expands to \( a^2 \pm 2ab + b^2 \).
Let's analyze the provided options:
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\(x^2 - 169\): This is a difference of squares, not a trinomial.
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\(16x^2 - 3x + 7\): This does not fit the pattern of a perfect square trinomial.
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\(4x^2 - 12x + 9\): We can check if this is a perfect square trinomial:
- Here, \(a^2 = 4x^2\) (so \(a = 2x\))
- \(b^2 = 9\) (so \(b = 3\))
- The middle term, \(2ab = -12x\) suggests \(-2(2x)(3) = -12x\).
Thus, \(4x^2 - 12x + 9 = (2x - 3)^2\), which confirms that it is a perfect square trinomial.
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\(25x + 1\): This is a linear expression, not a trinomial.
The correct answer is \(4x^2 - 12x + 9\).