<p>Well, you’ve gotta get m all by itself. It might help to remember that negative exponents mean the inverse of the positive exponent. So m^(-5) = 1/(m^5).</p>
<p>5m^(-5) * n^(-3) = 20m^3 * n
5/(m^5 * n^3) = 20m^3 * n <– simplify
5/(m^5) * n^4) = 20m^3 <– divide by n
5/(n^4) = 20m^8 <– multiply by m^5
1/(4n^4) = m^8 <– divide by 20
1/(2n^2) = m^4 <– take square root
1/(√(2)n) = m^2 <– take square root again
1/(2^(1/4)√n) = m <– take square root one more time</p>
<p>Annnnd, I should’ve checked that I agreed with your answer before I started typing. The answer you’re giving is equal to m^(-4), not m. Wolfram Alpha agrees with me (see link below). Where’d you get this question?</p>
<p>[5m^(-5)</a>; n^(-3) = 20m^3 * n - Wolfram|Alpha](<a href=“5m^(-5) n^(-3) = 20m^3 * n]5m^(-5) - Wolfram|Alpha”>5m^(-5) n^(-3) = 20m^3 * n - Wolfram|Alpha)</p>