Question

B1: Tính

a) \(.\sqrt{12,1.490}\)

b) \(\sqrt{72.32}\)

B2 : Rút gọn

a) \(\sqrt{48.75a^2}\)

b) \(\sqrt{8a^2}.\sqrt{18a^4}\) với a<0

c) \(\sqrt{a}.\sqrt{\dfrac{9}{a}}\left(a>0\right)\)

d)\(\sqrt{4-2\sqrt{3}}-\sqrt{3}\)

HELP ME !

Answer 1

B1: a) \(\sqrt{12,1.490}=\sqrt{12,1.10.49}=\sqrt{121}.\sqrt{49}=11.7=77\)

b) \(\sqrt{72.32}=\sqrt{36.2.32}=\sqrt{36}.\sqrt{64}=6.8=48\)

B2: a) \(\sqrt{48.75a^2}=\sqrt{3600a^2}=60\left|a\right|\)

b) \(\sqrt{8a^2}.\sqrt{18a^4}=\sqrt{8a^2.18a^4}=\sqrt{144a^6}=-12a^3\)

c) \(\sqrt{a}.\sqrt{\dfrac{9}{a}}=\sqrt{a.\dfrac{9}{a}}=\sqrt{9}=3\)

d) \(\sqrt{4-2\sqrt{3}}-\sqrt{3}=\sqrt{\left(\sqrt{3}-1\right)^2}-\sqrt{3}=\sqrt{3}-1-\sqrt{3}=-1\)