-7(-a^2)(-b^3)

-7(-a^2)(-b^3)

Simply multiply out all the terms and note that we have 3 negatives [since 2 negatives make a positive or plus, we are left with +*- which means we end up with a negative, -].

So, our answer is: -7a^2b^3.

-7(a^2)(-b^3)

$${\mathtt{\,-\,}}\left({\mathtt{7}}{\mathtt{\,\times\,}}\left({{\mathtt{a}}}^{{\mathtt{2}}}{\mathtt{\,\times\,}}\left({\mathtt{\,-\,}}\left({{\mathtt{b}}}^{{\mathtt{3}}}\right)\right)\right)\right)$$

-7*$${\mathtt{\,-\,}}\left({{\mathtt{a}}}^{{\mathtt{2}}}{\mathtt{\,\times\,}}{{\mathtt{b}}}^{{\mathtt{3}}}\right)$$

-7-(a^2-b^3)

-7a^2b^3 This is the finally anwser