Find the first, fourth, and eighth terms of the sequence. a(n)=-2 x 2^n-1

2, 16 and 256.

Step-by-step explanation:

Just substitute  for n:-

first term ( when n = 1) =  2 * 2^(1-1)

= 2 * 1 =  2

4th term =  2 * 2^(4-1) =  16

8th term = 2* 2^(8-1) = 256

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

22

step-by-step explanation:

22