[tex]\bf (-4k^4j^5)^3(k^3j^3)^7\impliedby \textit{first off, let's distribute the exponent}
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[(-4)^3k^{4\cdot 3}j^{5\cdot 3}]~~~(k^{3\cdot 7}j^{3\cdot 7})\implies -64k^{12}j^{15}~~~~~k^{21}j^{21}
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-64k^{12+21}j^{15+21}\implies -64k^{33}j^{36}[/tex]