im trying to rewrite -(3/5)^-2 without a negitve exponent>

You use the reciprocal of (3/5) because a number to a negative exponent is the same as 1 over the number to the positive form of the exponent.

So - (3/5) ^ -2 is the same as - (1/(3/5)) ^ 2.

So:

$${\mathtt{\,-\,}}\left({\left({\frac{{\mathtt{3}}}{{\mathtt{5}}}}\right)}^{-{\mathtt{2}}}\right) = {\mathtt{\,-\,}}{\frac{{\mathtt{25}}}{{\mathtt{9}}}} = -{\mathtt{2.777\: \!777\: \!777\: \!777\: \!777\: \!8}}$$

And $${\mathtt{\,-\,}}\left({\left({\frac{{\mathtt{5}}}{{\mathtt{3}}}}\right)}^{{\mathtt{2}}}\right) = {\mathtt{\,-\,}}{\frac{{\mathtt{25}}}{{\mathtt{9}}}} = -{\mathtt{2.777\: \!777\: \!777\: \!777\: \!777\: \!8}}$$