What is the supplement of 123°

Solve the system of equations y= 3/2 - 1, -x+ y =-3

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83