Answer:
930
Step-by-step explanation:
1) Once upon a time there was a bored kid in class who invented a super cool formula
This formula goes like this:
n(n+1)
where n= the sum of the first n numbers in a series
so
30(30+1)=30(31)=930
10mn -35m
8rs-2r^2+16r
they are in order.
10
Negative times a negative is a positive.
so 12-2=10
21
just because whsusjeej
hope this can help you (^^)
