13 tháng 7 2021 lúc 6:16
a: \(\sqrt{0,36a^2}=\sqrt{0,36}\cdot\sqrt{a^2}\)
\(=0,6\cdot\left|a\right|=-0,6a\left(a<0\right)\)
b: a>=3
=>a-3>=0
\(\sqrt{a^4\left(3-a\right)^2}\)
\(=\sqrt{a^4}\cdot\sqrt{\left(a-3\right)^2}\)
\(=a^2\cdot\left(a-3\right)\)
c:
a>1
=>a-1>0
\(\sqrt{27\cdot48\cdot\left(1-a\right)^2}\)
\(=\sqrt{3^3\cdot3\cdot2^4\cdot\left(a-1\right)^2}\)
\(=\sqrt{3^4\cdot2^4}\cdot\sqrt{\left(a-1\right)^2}=3^2\cdot2^2\cdot\left|a-1\right|=36\left(a-1\right)\) (a-1>0)
=36a-36
d:
a>b
=>a-b>0
\(\frac{1}{a-b}\cdot\sqrt{a^4\left(a-b\right)^2}\)
\(=\frac{1}{a-b}\cdot a^2\cdot\left|a-b\right|=a^2\cdot\frac{\left(a-b\right)}{a-b}\)
\(=a^2\)
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giúp mình ý a là đc ạ mình cảm ơn ạ
