three numbers of a geometric progression whose sum is 28 and whose product is 512. find the first three numbers
the problem above, i have attempted it and arrived at 8,16,32
am i correct? thanks
As Plato has shown, your solution can not possibly be right.
You have
$\displaystyle \displaystyle \begin{align*} t_n + r\,t_n + r^2t_n &= 28 \\ (r^2 + r + 1)t_n &= 28 \end{align*}$
and
$\displaystyle \displaystyle \begin{align*} t_n \cdot r\,t_n \cdot r^2t_n &= 512 \\ r^3t_n &= 513 \end{align*}$
Try to solve these two equations simultaneously to find $\displaystyle \displaystyle \begin{align*} r \end{align*}$ and $\displaystyle \displaystyle \begin{align*} t_n \end{align*}$. From there you can find the following two terms.