Question

Find S10 for -1 + -7 +-13 + -19 +...

Answer 1

@SolomonZelman last one, I promise!

Answer 2

I don't mind. Trig is my best class. I had a 98 in a semester exam, and 100 on the final :)

Answer 3

wow!

Answer 4

way smarter than me, good thing we have openstudy haha thanks

Answer 5

\(\large\color{red}{ \rm d=-6}\)

\(\large\color{red}{ \rm a_{10}=-1+(-6)(10-1)=-1+(-54)=-55}\)

\(\large\color{red}{ \rm S_{10}=~½(a_{10}+a_1)10=½(-55+-1)10=(-56)5=?}\)

Answer 6

-55?

Answer 7

Read my reply please, how are you getting-55 ?

Answer 8

-55 is only A10, but we are at S10 already, no ?

Answer 9

Im sorry I cant solve it :(

Answer 10

@SolomonZelman

Answer 11

Just read my reply in red. I promise, it is not so hard :)

Answer 12

I keep getting -55 @SolomonZelman