в) 4√a3b2.5a4b3 ;

в) $$4√a^3b^2 .5a^4b^3 = 4\sqrt[4]{a^3b^2} \cdot 5\sqrt{a^4b^3} = 5a \sqrt{b} 4\sqrt[4]{a^3b^2} = 5a 4\sqrt[4]{a^3b^2b^2} = 5a 4\sqrt[4]{a^3b^4} = 5ab4\sqrt[4]{a^3}$$.

Ответ: $$5ab4\sqrt[4]{a^3}$$