Express the following sums using summation notation: (-3) + (-2) + (-1) + 0 + 1 + 2 + 3 + 4 3^4 + 3^5 + 3^6 + 3^7 + 3^8 + 3^9 2^3 + 3^4 + 4^5 + 5^6 + 6^7 + 7^8 The sum of the cubes of the first 12 positive integers The sum of the cubes of the even integers between 1 and 99