-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