Question

find the sum of the first 7 terms og G.P -4,12,-36,.........​

Answer 1

Answer:

The sum of the first 3 terms of GP is 7 and the sum of their squares is 21.

Step-by-step explanation:

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Answer 2

Answer:

728

Step-by-step explanation:

a = -4 , b = 12 , c =-36

S7 = a (1 - r^n)/1-r

= -4{1-(-3)^7}/ 1-(-3)

= -4{1-729} / 1+3

= - ( -728)

= 728