Given expression: [tex]\frac{-3a^{-2}b^3}{15a^{-7}b^{-1}\:}[/tex].
We need to find the simplified expression after eliminating negative exponents.
According to rules of negative exponents, the negative exponents terms get switch from top to bottom and bottom to top by making exponent positive.
Therefore, [tex]a^{-2}[/tex] would go in the bottom, and [tex]a^{-7}b^{-1}[/tex] would go on the top by making exponents positive.
So, it would become :[tex]\frac{-3a^{7}b^3b^{1}}{15a^2}[/tex].