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\(16a^2-b^2=\)

• \((4a-b)(4a-b)\)
• \((16a-b)(16a+b)\)
• \((4a-b)(4a+b)\)

\(49a^2b^2-c^4=\)

• \((7ab-c^2)(7ab-c^2)\)
• \((7ab-c^2)(7ab+c^2)\)
• \((7ab-c)(7ab+c)\)

\(\dfrac{1}{4} a^2 -\dfrac{1}{3}a+\dfrac{1}{9}=\)

• \((\cfrac12 a-\cfrac13)(\cfrac12 a+\cfrac13)\)
• \((\cfrac12 a-\cfrac13)^2\)
• \((\cfrac12 a-\cfrac13)(\cfrac12 a-\cfrac13)\)