#### Answer

($\frac{-4}{7}$,$\frac{16}{49}$)

#### Work Step by Step

($\frac{2}{3}$,$\frac{4}{9}$),($\frac{1}{5}$,$\frac{1}{25}$),(7,49),($\frac{-5}{6}$,$\frac{25}{36}$),($\frac{-4}{7}$,_)
In every interval the second number is square of the first number
So in the last interval the second number is $\frac{16}{49}$
($\frac{-4}{7}$,$\frac{16}{49}$)