Please help me i need answers to part a and b

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

1c) the number 131 is a term in the sequence defined by the explicit rule f(n)=5n-4. which term in the sequence is 131? 2a) write the first four terms of the function f(n)=n^2-1 2b) what is the 10th term of the sequence defined by the explicit rule f(n)=n^2-1 2c) the number 224 is a term in the sequence defined by the explicit rule f(n)=n^2-1. which term in the sequence is 224?

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