Question

I need help with #8 and #9 Please! :) I will mark as brainliest!

Answer 1

Answer:

see explanation

Step-by-step explanation:

(8)

the common ratio r,  of a geometric sequence is

r = $\frac{a_{2} }{a_{1} }$ = $\frac{a_{3} }{a_{2} }$ = ......

r = $\frac{\frac{1}{32} }{\frac{1}{256} }$ = $\frac{\frac{1}{4} }{\frac{1}{32} }$ = 8

(9)

The simplest way to evaluate the sum is to substitute k = 3, 4, 5, 6 into each term and sum them

(- 9 + 20) + (- 12 + 20) + (- 15 + 20) + (- 18 + 20)

= 11 + 8 + 5 + 2 = 26