Copying what Arjun Sir answered and adding little more
A trivial solution to a problem means, it is a valid solution for any problem of the same type. i.e., this solution is known to anyone and hence there is no use in explicitly mentioning it. For example, in a homogenous solution where equation equated to 0, putting all variables equal to 0 is a correct solution, but this is not a useful one and hence never really asked in any question.
Homogeneous equation are equation which are like A.X=0
Homogeneous solution of equation will never have unique solution because they already have trivial and zero solution. Hence homogeneous equation can have
1) Trivial solution when rank(A) =n (n is number of unknown) and Det(A) != 0 (non singular) and
2) Infinite solution. .. when det(A) =0 (singular) they will have infinite solution.
A matrix "B" is said to be singular when Det(B) =0 ..
A matrix "C" is said to be non singular when Det(C) != 0