Question

-3(1+6^8)/(1-6) I got -384,320 which i think is wrong. I first did 7^8 divided by 5 divided by -3. What did i do wrong?

Answer 1

well the answer will be positive

the steps

1. 6^8

2. add 1

3. multiply by -3

4. divide by (1 - 6) or -5

Answer 2

I got 1007770.2 which is also wrong, the answers are a. 719,835
b. 119,973
c. -119,973
d. -719,835

Answer 3

I also got 1 007 770,2 and I don't see any mistake in your calculations. If you multiply (1+6^8) by -3 you get 5 038 851 which you then divide by -5 to get 1 007 770,2. And I'm sure the result should be positive since both the numerator and the denominator are negative (if you were to write it as a fraction).

Answer 4

well maybe i set up the problem wrong? >_< the question is What is the sum of the geometric sequence -3, 18, -108, ... if there are 8 terms?

Answer 5

Oh cool I recently had a test on arithmetic and geometric sequences.
I think you miscalculated the quotient. It is -6 (18/(-3) or (-108)/18))
The formula was ok anyway so the right way to write the problem would be:
\[\frac{ -3*(-6^{8}-1) }{ -6-1}\] The result I got is -719 835,86

Answer 6

ooooooo thank you!