Answer:
r = - 2.5

Step-by-step explanation:
21r - 7 - r + 5 = - 52
20r - 2 = - 52
20r - 2 + 2 = - 52 + 2
20r = - 50
20r ÷ 20 = - 50 ÷ 20
r = - 2.5
Answer:
The answer is the 2nd choice
Step-by-step explanation:
The ladder makes 79.92 degrees of angle with the ground (Calculation: Cos A = 7/40 = 0.175 resulting A = ACos 0.175 = 79.92 degrees). This problem can be solved by using a simple trigonometry formula of Cosine which stated Cos A = Adjacent/Hypotenuse. The ladder length of 40 feet is the hypotenuse side of the triangle and the 7 feet distance between the ladder's foot and the wall is the adjacent side<span>. </span>
Answer:
Part A


Part B
Geometric Sequence
Part C
1/4,3/4,5/4,7/4,9/4

Part D:

Step-by-step explanation:
By definition, an Arithmetic Sequence holds the same difference between each following number.
Part A

<u>Explicit Formula</u>
To write an explicit formula is to write it as function.

<u>Recursive Formula</u>
To write it as recursive formula, is to write it as recurrence given to some restrictions:

Part B

Geometric Sequence, since 2*2=4 8*2=16 and 16*2=32 and 8+2=10 8+16=24
Part C

Arithmetic Sequence, difference

<u>Explicit Formula:</u>

<u>Recursive Formula</u>

Part D
(1.1,1.5,1.9,2.3,2.7) Arithmetic Sequence, difference d=0.4
<u>Explicit formula</u>

<u>Recursive Formula</u>

S = (10 x1 /2) + (1/2x- 2x 1/2²)
5 + (-0.25)
= 4.75