Problem
NT-B1-M04-P008 The Congruence \(9x\equiv6\)
#8
★★☆☆☆ Level 2 of 5
Solve \(9x\equiv6\pmod{15}\).
Reduce by \(\gcd(9,15)=3\).
We get \(3x\equiv2\pmod5\). The inverse of \(3\) modulo \(5\) is \(2\), so \(x\equiv4\pmod5\). Modulo \(15\): \(x\equiv4,9,14\).
Another practice on number of solutions.