Here's a pattern to consider:
1+100=101
2+99=101
3+98=101
4+97=101
5+96=101
.....
This question relates to the discovery of Gauss, a mathematician. He found out that if you split 100 from 1-50 and 51-100, you could add them from each end to get a sum of 101. As there are 50 sets of addition, then the total is 50×101=5050
So, the sum of the first 100 positive integers is 5050.
Quick note
We can use a formula to find out the sum of an arithmetic series:

Where s is the sum of the series and n is the number of terms in the series. It works for the above problem.
Answer:
Thanks!
Step-by-step explanation:
Hey Again hows your day?
The number beside the letter . for example 6x, 6 would be the variable
Answer:
x=7
Step-by-step explanation:
To set up for this answer, we need to set it up as an equation: 2x+12=5x-9.
get the xs on one side and the whole numbers on the other.
that leaves you with 21=3x.
divide by 3 on both sides to get the answer of x=7