# Quadratic residues and composite moduli

Which of the following statements are true?

(1) 73 is a quadratic residue mod 5.

(2) 73 is a quadratic residue mod 83.

(3) 73 is a quadratic residue mod 415.

(4) $$\left( \dfrac{73}{415} \right) = 1,$$ where $$\left( \dfrac{a}{n} \right)$$ is the Jacobi symbol.

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