Pablo folds a straw into a triangle with side lengths of 4x2−3 inches, 4x2−2 inches, and 4x2−1 inches. Which expression can be used to find the perimeter of the triangle, and what is the perimeter when x = 1.5?

Add the three side lengths: (4x² − 3) + (4x² − 2) + (4x² − 1) = 12x² − 6. When x = 1.5, the perimeter is 12(1.5²) − 6 = 12(2.25) − 6 = 21 inches. Choice A gives both the expression and the perimeter.

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