Đáp án:
a) 3$\sqrt[]{5}$ = $\sqrt[]{32.5}$ =$\sqrt[]{45}$
b) 1,2$\sqrt[]{5}$ = $\sqrt[]{1,22.5}$ = $\sqrt[]{7,2}$
c) ab4$\sqrt[]{a}$ = √((ab4)2 a)= $\sqrt[]{a^2.b^8a}$ = $\sqrt[]{a^3.b^8}$
d) -2ab2$\sqrt[]{5a}$ = -$\sqrt[]{(2ab^2)^2.5a}$ = -$\sqrt[]{4a^2.b^4.5a}$ = -$\sqrt[]{20a^3b^4}$