1+3+5+7+...+999 =
= 1+2+3+4+...+500
+1+2+3+...+499
= 2·(1+2+3+...+499) + 500
= 2·(499·500)/2 + 500
= 499·500 + 500
= 500·(499 + 1)
= 500·500
= 250.000
I think the correct one is C. 130
Answer:
The answer is A) -1 + 12i
Step-by-step explanation:
(7 + 3i) + (-8 + 9i)
(7 - 8) + (3 + 9)i
7 - 8 = - 1
3 + 9 = 12
- 1 + 12
