Answer:
9 sq ft
Step-by-step explanation:
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Given information
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Area = 40ft²
Length = √20 ft
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Formula
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Area = Length x Width
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Find Width
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40 = √20 x width
Width = 40 ÷ √20
Width = 40 ÷ 2√5
Width = 20 ÷ √5

You're original equation has a -81, so the factored form will have to have a positive and negative multiplying one another to achieve that...
f(x) = x(x + 9)(x - 9)
Answer:
5
Step-by-step explanation:
1. Add -8 to -12. This equals -20.
2. Now you have -20/(-4)
3. Solve this by dividing -20 and -4.
4. Two negatives make a positive, so your answer would be 5.
Hope this helps