We have 50 groupings of parentheses. We can tell because the first parentheses has a +1 and the last parentheses has a +50. 50 * 2x = 100x Now we have to find 1 + 2 + 3 + ... + 50. Add 1 and 50 together. Now add 2 and 49 together. Add 3 and 48 together. Notice how each pair sums to 51. We have 50/2 = 25 pairs and each pair equals 51. 25*51 = 1275 100x + 1,275 = 4,275 100x = 3000 x = 30
