Question

solve for r

Answer 1

\[u_{1} + u _{1}r + u _{1}r ^{2}=(7/8)((u _{1})/(1-r)) \]

Answer 2

\[u_{1}+u_{1}r+u_{1}r^2=\frac{7}{8}\frac{u_{1}}{1-r}?\]

Answer 3

Have you tried dividing both sides by\[u_{1}?\]

Answer 4

\[1+r+r^2=\frac{7}{8}\frac{1}{1-r}.\]

Answer 5

I got that far then everything after that didn't turn out right

Answer 6

\[(1-r)(1+r+r^2)=\frac{7}{8}\]

Answer 7

Oh ok, I might be able to solve the rest from there

Answer 8

:)

Answer 9

there's another part. Are you familiar with sequences and series?