a beach is disappearing at a rate of -5 feet per year. How long will it take for the beach to lose 85 feet?

The graph below shows the amount of money left in the school’s desk fund, f, after d desks have been purchased. for each new desk that is purchased, by how much does the amount of money left in the school’s desk fund decrease?

Will give brainliest series to sigma notation write the following series in sigma notation. 6+10+14+18+22+26+30 example image shown below.

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.