1. 27, 42, 57, 72, ___Common difference (d): 1572+15=872. 12, -15, -18, -21, ___Common difference (d): -3−21+(−3)= −243. 83, 92, 101, 110, 119, ___Common difference (d): 9119+9=128 4. 14, 7, 0, -7, -14, ___Common difference (d): -7−14+(−7)= −215. 23, 40, 57, 74, 91, ___Common difference (d): 1791+17= 108QUADRATIC SEQUENCESA quadratic sequence has a second common difference (difference of the differences).1. -3, -13, -31, -57, -91, ___1st differences: -10, -18, -26, -342nd differences: -8 (constant)Next 1st difference: -34 - 8 = -42Next term: -91 + (-42) = -1332. 4, 11, 20, 31, 44, ___1st differences: 7, 9, 11, 132nd differences: +2Next 1st difference: 13 + 2 = 15Next term: 44 + 15 = 593. 3, 13, 27, 45, 67, ___1st differences: 10, 14, 18, 222nd differences: +4Next 1st difference: 22 + 4 = 26Next term: 67 + 26 = 93