Answer:
6x + 10, all ready simplified
Step-by-step explanation:
It's not the difference of squares, rather it is the square of a difference. That leaves a perfect square trinomial, which narrows your selection to two choices. An expression with 2 terms is not a trinomial, so that further narrows your selection. The appropriate choice is
... (4xy -3z)² = 16x²y² -24xyz +9z², a perfect square trinomial
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The expression you have in your problem statement has no z term, so none of the choices is applicable to that one.
s = 2(lw + lh + wh)
Divide each side by 2 : s/2 = lw + lh + wh
Subtract 'lh' from each side: s/2 - lh = lw + wh
Combine the 'w' terms: s/2 - lh = w(l + h)
Divide each side by (l + h): (s/2 - lh) / (l + h) = w