Henry's mistakes were on line 3:
1. He wrote that the square of -3 is -6. When in fact, it should have been 9
2. He did not add the powers of "a" properly. Had He done it properly, He would have gotten 3 + 4 = 7 as the power of "a"
Thus, after correcting his errors, His solution ought to be:
[tex]\begin{gathered} (-5ab)^3.(-3a^2b^2)^2 \\ (-5)^3a^3b^3\text{.}(-3)^2a^{2+2}b^{2+_{}2}_{} \\ -125a^3b^3.9a^4b^4 \\ -1125a^{3+4}b^{3+4} \\ \text{full answer = -1125a}^7b^7 \end{gathered}[/tex]
