Given that there are six terms, we have this set:
So, we need to find a4 and a5. Given that:
-9-(-7) = -2
-11-(-9) = -2
Then, it is obvious that
∴
∴
Then, <span>the sum of the terms of the series is</span>:
There are two answers:
2y+2y=4y
Y+y+y+y=4y
840 = 1×840=2×420 = 3×280 = 4×210 = 5×168 = 6×140 = 7×120 = 8×105
4220=1×4220 = 2×2110 = 4×1055 = 5×844
2840 = 1×2840 = 2×1420 = 4 × 710 = 5 × 568 = 8 × 355