Question

Rút gọn:

a,\(\sqrt{4\left(a-3\right)^2}với\) \(a\ge3\)

\(b,\sqrt{9\left(b-2\right)^2}với\) \(b< 2\)

\(c,\sqrt{27.48\left(1-a\right)^2}với\) \(a>1\)

\(d,\sqrt{5a}.\sqrt{45a}-3a\) \(với\) \(a\ge0\)

\(e,\dfrac{\sqrt{48x^3}}{\sqrt{3x^5}}với\) \(x>0\)

Answer 1

a)\(\sqrt{4\left(a-3\right)^2}=\sqrt{2^2\left(a-3\right)^2}=\sqrt{\left(2a-6\right)^2}=2a-6\)

b) \(\sqrt{9\left(b-2\right)^2}=\sqrt{3^2\left(b-2\right)^2}=\sqrt{\left[3\left(b-2\right)\right]^2}=3b-6\)

c) bạn xem lại đề

d)
\(\sqrt{5a}.\sqrt{45a}-3a=\sqrt{225a^2}-3a=\sqrt{\left(15a\right)^2}-3a=15a-3a=12a\)

Answer 2

e) \(\dfrac{\sqrt{48x^3}}{\sqrt{3x^5}}=\sqrt{\dfrac{48x^3}{3x^5}}=\sqrt{\dfrac{16}{x^2}}=\dfrac{\sqrt{16}}{\sqrt{x^2}}=\dfrac{4}{x}\)