Answer
$a^{127}b^{86}c^{25}$
Work Step by Step
$(a^{20}b^{10}c^{5})^{5}(a^{9}b^{12})^3$
$(a^{20})^5(b^{10})^5(c^5)^5(a^9)^3(b^{12})^3$
$(a^{100})(b^{50})(c^{25})(a^{27})(b^{36})$
$a^{127}b^{86}c^{25}$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.