Answer:
<em>The second choice is correct. It can be factored as:</em>

Step-by-step explanation:
<u>The Difference of Squares Method for Factoring</u>
The expression:

Is a widely used method to factor binomials that are expressed as the subtraction of two perfect squares.
The condition for a binomial to be factored by using this method is that both terms must have an exact square root and they must be subtracted.
The last two choices are not valid because they are not a subtraction but an addition.
The first choice is not valid because none of the terms is a perfect square.
The second choice is correct. It can be factored as:

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Answer:
Total length of iron needed to make the square frame and two diagonals = 43.44 in (Approx)
Step-by-step explanation:
Given:
Length of diagonal = 9 in
Find:
Total length of iron needed to make the square frame and two diagonals.
Computation:
Area of square = 1/2(diagonal)²
Area of square = 1/2(9)²
Area of square = 40.5 in²
Area of square = Side × Side
40.5 in² = Side × Side
Side = 6.36 (approx)
Total length of iron needed to make the square frame and two diagonals = Permeter of square + (2 × diagonal)
⇒ (4 × 6.36) + (2 × 9)
⇒ (25.44) + (18)
⇒ 43.44 in
Total length of iron needed to make the square frame and two diagonals = 43.44 in (Approx)