Exercise 9.
Determine which of the following congruences have solutions, and find any solutions (between 0 and the modulus) by trial and error.
\(4x \equiv 5 \pmod 7\text{.}\)
\(6x \equiv 4 \pmod 9\text{.}\)
\(x^2 \equiv 2 \pmod 7\text{.}\)
Determine which of the following congruences have solutions, and find any solutions (between 0 and the modulus) by trial and error.
\(4x \equiv 5 \pmod 7\text{.}\)
\(6x \equiv 4 \pmod 9\text{.}\)
\(x^2 \equiv 2 \pmod 7\text{.}\)