Question

29. E = 1 x 2 + 2 x 3 + 3 x 4 + 4 x 5 +... 25 x 26

Answer 1

1×2

+

2×3

____

8

3×4

+

4×5

____

32

25

×

26

____

650

650+32+8=690

espero haberte ayudado xd