# Quadratic residues and composite moduli

**Number Theory**Level 4

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.