Question

\(a.\sqrt{4a^2}voi\:a\ge0\)
\(b.\sqrt{0,16\left(x-2\right)^2}voi\:x\ge2\)
\(c.\sqrt{25.\left(3-a\right)^2}+3\)
\(d.\frac{1}{2\left(x-5\right)}\sqrt{36.\left(x-5\right)^2}-5\:voi\:x\ne5\)

Answer 1

a/ \(\sqrt{4a^2}=\sqrt{\left(2a\right)^2}=\left|2a\right|=2a\)

b/ \(\sqrt{\left(\frac{2}{5}\right)^2\left(x-2\right)^2}=\frac{2}{5}\left|x-2\right|=\frac{2}{5}\left(x-2\right)=\frac{2x}{5}-\frac{4}{5}\)

c/ \(\sqrt{5^2\left(3-a\right)^2}+3=5\left|3-a\right|+3=\left[{}\begin{matrix}18-5a\left(a\le3\right)\\5a-12\left(a\ge3\right)\end{matrix}\right.\)

d/ \(=\frac{1}{2\left(x-5\right)}.6\left|x-5\right|=\frac{3\left|x-5\right|}{x-5}=\left[{}\begin{matrix}3\left(x>5\right)\\-3\left(x< 5\right)\end{matrix}\right.\)