16/2 (2a + 15d) = -504
9/2 (2a+8d) = -126
Solve for a and d, then find
30/2 (2a+29d)
the sum of 16 terms of an A.P.is -504,while the sum of its 9 terms is -126.find the sum of its 30 terms.
2 answers
How did you get the a and d nauu???