( - 6 xm³a⁴)³

To simplify the expression (-6xm³a⁴)³, we need to cube each term inside the parentheses and then combine any like terms.

(-6xm³a⁴)³ = (-6)³(xm³)³(a⁴)³

Using the rule (ab)³ = a³b³, we can simplify further:

(-6)³(xm³)³(a⁴)³ = -6³(x³m³³)(a⁴)³

(-6)³ = -6 * -6 * -6 = -216

(x³)³ = x^(3*3) = x^9

(m³³) = m^(3*3) = m^9

(a⁴)³ = a^(4*3) = a^12

Putting it all together, we get:

-216x^9m^9a^12