## anonymous one year ago Find the sum of the summation of 2 i minus 9, from i equals 3 to 10.

1. anonymous

$\sum_{3}^{10}2i-9$?

2. anonymous

yes, except at the bottom of that E thing, its i=3

3. anonymous

got it a few steps are needed ready?

4. anonymous

yes

5. anonymous

first replace $$i$$ by $$3$$ in $$2i-9$$ what do you get ?

6. anonymous

-3?

7. anonymous

lol yeah $$-3$$!!

8. anonymous

now hold on to that number for a sec replace $$i$$ by $$10$$ in $$2i-9$$ what do you gte ?

9. anonymous

11

10. anonymous

ok now add those two numbers

11. anonymous

8?

12. anonymous

yup now divide that by 2

13. anonymous

4

14. anonymous

one more step

15. anonymous

which might be a little confusing you actually have 8 terms to add up $$10-3+1=8$$ take your 4 and multiply it by 8

16. anonymous

32

17. anonymous

18. anonymous

want to check it?

19. anonymous

I turned in the test. It was right. Thank you so much!

20. anonymous

you are quite welcome

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