A famous Hindu mathematician, Aryabhata, showed (in around 500 C. E.) you could add up the first n triangular numbers with a relatively simple formula: n(n + 1)(n + 2) =T + T2 + T3 + ... + Tn 6 Use this fact to find the sum of the first 53 triangular numbers. The sum of the first 53 square numbers is

Acable company claims that the average household pays $78 a month for a basic cable plan, but it could differ by as much as $20. write an absolute value inequality to determine the range of basic cable plan costs with this cable company. a. |x − 78| ≥ 20 b. |x − 20| ≥ 78 c. |x − 20| ≤ 78 d. |x − 78| ≤ 20