Đáp án:
a, $\dfrac{a}{2}$
c, $12a$
d, $a^2-12a+9$
Giải thích các bước giải:
a, $\sqrt{\dfrac{2a}{3}}.\sqrt{\dfrac{3a}{8}}=\sqrt{\dfrac{2a.3a}{3.8}}=\sqrt{\dfrac{a^2}{4}}=\dfrac{a}{2}$
c, $\sqrt{5a}.\sqrt{45a}-3a=\sqrt{5a.45a}-3a=\sqrt{225a^2}-3a=15a-3a=12a$
d, $(3-a)^2-\sqrt{0,2}.\sqrt{180a^2}=9-6a+a^2-\sqrt{0,2.180a^2}$
$=9-6a+a^2-\sqrt{36a^2}=9-6a+a^2-6a=a^2-12a+9$
