WILL MARK BRAINLIEST! 4. Find the sum of the first 21 terms in a series where a = 20 and = 400.
5. Find the sum of the first 100 terms in a series where a = 0 and = 99.
6. Find the sum of the first 50 terms in a series where a = 4 and = 196.
7. Find the sum of the first 100 terms in a series where a = 0 and = 99.
8. Find the sum of the first 10 terms in an arithmetic series where = 7 and = 13.
9. Find the sum of the first 10 terms in an arithmetic series where = 15 and = 45.
10. Find the sum of the first 30 positive multiples of 5.
Part B
Directions: Now, find n and Sn for each of the following arithmetic series below.
11. 5 + 11 + 17 + 23 + …+ 101
12. 2 + 4 + 6 + 8+ …+ 60
13. 46 + 43 + 40 + …+ 16

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations:

3.how is solving radical equations different than solving linear equations?

step-by-step explanation:

correct answer:

b.(19,-2)

step-by-step explanation:

options