\(\sqrt{48\cdot45}=12\sqrt{15}\\ \sqrt{225\cdot17}=15\sqrt{17}\\ \sqrt{a^3b^7}=\left|ab^3\right|\sqrt{ab}=ab^3\sqrt{ab}\\ \sqrt{x^5\left(x-3\right)^2}=\left|x^2\left(x-3\right)\right|\sqrt{x}=x^2\left(x-3\right)\sqrt{x}\)

\(\sqrt{48\cdot45}=4\sqrt{3}\cdot3\sqrt{5}=12\sqrt{15}\)

\(\sqrt{225\cdot17}=15\sqrt{17}\)

a: \(\sqrt{5a^2}=\left|a\sqrt{5}\right|=-a\sqrt{5}\left(a< =0\right)\)

c: A=\(\sqrt{72a^2b^4}=\sqrt{36a^2b^4\cdot2}=6\sqrt{2}\cdot b^2\cdot\left|a\right|\)

mà a<0

nên \(A=-6\sqrt{2}\cdot ab^2\)

d: \(\sqrt{24a^4b^8}=\sqrt{4a^4b^8\cdot6}=2a^2b^4\cdot\sqrt{6}\)

a/ \(\sqrt{50a}=5\sqrt{2a}\)

b/ \(\sqrt{75x}=5\sqrt{3x}\)

a)\(5\sqrt{2a}\)

b)\(5\sqrt{3x}\)

a) \(\sqrt{50a}=\sqrt{25.2}=5\sqrt{2a}\)

b) \(\sqrt{75x}=\sqrt{25.3x}=5\sqrt{3x}\)

8 y 2 = 4 . 2 y 2 = 2 y 2 = - 2 y 2 ( với y < 0 )

√(28a4b2 ) = √((2a2b)2.7) = √7 |2a2b| = 2√7a2b (do b ≥ 0)

25 x 3 = 25 x 2 . x = 5 x x = 5 x x ( với x > 0 )

7 x 2 = x 7 = x 7 ( với x > 0 )

\(\sqrt{18b^3\cdot\left(1-2a\right)^2}\)

\(=3\sqrt{2}\cdot b\sqrt{b}\cdot\left|1-2a\right|\)

\(=3\sqrt{2}\left(2a-1\right)\cdot b\sqrt{b}\)

b)  63 y 3 7 y với y > 0

=  63 y 3 7 y = 9 y 2 = 3 y = 3 y do y > 0