Quadratic Residues

Is 5 a quadratic residue modulo 7?

Which of these is the set of non-quadratic residues modulo $11$ ?

B=\{ 2,6,7,8,10 \}

A=\{ 0,1,3,4,5,9 \}

D=\{ 2,4,6,8,10 \}

C=\{ 0,1,2,3,4,5,6,7,8,9,10 \}

Which of these is the set of quadratic residues modulo $15$ ?

\{0,1,4,6,9,10 \}

\{ 0,1,3,8,12 \}

\{ 0,1,5,6,13 \}

\{ 0,1,4,7,14 \}

Find the sum of all positive integers $x<22$ such that $x^2 \equiv 17 \pmod {22}$ .

Is $15$ a quadratic residue modulo $17$ ?

Quadratic Residues - Primes