Answer:
When you have two negative signs, one turns over, and they add together to make a positive. If you have a positive and a negative, there is one dash left over, and the answer is negative.
<em>I hope this was the answer you were looking for - Lily~Senpai :P</em>
Answer:
B = 25050
Step-by-step explanation:
S=n/2(2a1+(n-1)d)
The answer is 25/ 3 Good luck