Question

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Explanation:

Step1: Apply distributive property

$(n-7)(3n+1) = n(3n+1) -7(3n+1)$

Step2: Expand each term

$= 3n^2 + n -21n -7$

Step3: Combine like terms

$= 3n^2 + (n-21n) -7$

Answer:

$3n^2 -20n -7$