а) $$(mn)^6 = m^6n^6$$
б) $$(2ab)^3 = 2^3a^3b^3 = 8a^3b^3$$
в) $$(-3x)^4 = (-3)^4x^4 = 81x^4$$
г) $$(-10xy)^5 = (-10)^5x^5y^5 = -100000x^5y^5$$
Ответ: а) $$m^6n^6$$, б) $$8a^3b^3$$, в) $$81x^4$$, г) $$-100000x^5y^5$$