d) \(\dfrac{1}{3}\sqrt{225a^2}=\dfrac{1}{3}\sqrt{\left(15a\right)^2}=\dfrac{1}{3}\left|15a\right|=\left|5a\right|\)
\(\Rightarrow\left[{}\begin{matrix}a>0\Rightarrow d=5a\\a< 0\Rightarrow d=-5a\end{matrix}\right.\)
Giải:
a) \(\sqrt{49.360}\)
\(=\sqrt{7^2.3^2.2^2.10}\)
\(=7.3.2\sqrt{10}\)
\(=42\sqrt{10}\)
Vậy ...
b) \(-\sqrt{500.162}\)
\(=-\sqrt{10^2.5.9^2.2}\)
\(=-10.9\sqrt{10}\)
\(=-90\sqrt{10}\)
Vậy ...
c) \(\sqrt{125a^2}\)
\(=\sqrt{5^2.5.a^2}\)
\(=\sqrt{5^2.5.\left(-a\right)^2}\)
\(=-5a\sqrt{5}\)
Vậy ...
d) \(\dfrac{1}{3}\sqrt{225.a^2}\)
\(=\dfrac{1}{3}\sqrt{15^2.a^2}\)
\(=\dfrac{1}{3}.15.a^2\)
\(=5a^2\)
Vậy ...
a,\(\sqrt{49.360}\)
=\(\sqrt{49.36.10}\)
=\(\sqrt{7^2.6^2.10}\)
=\(42\sqrt{10}\)
b,\(-\sqrt{500.162}\)
=\(-\sqrt{25.4.5.162}\)
=\(-\sqrt{25.4.81.10}\)
=\(-\sqrt{5^2.2^2.9^2.10}\)
=\(-90\sqrt{10}\)
c,\(\sqrt{125a^2}vớia< 0\)
=\(\sqrt{25.5.a^2}\)
=\(\sqrt{5^2.5.a^2}\)
=\(5\left|a\right|\sqrt{5}\)
Vì a<0 ⇒
=\(-5a\sqrt{5}\)
d,Câu này giải rồi nên thôi mk ko làm lại nữa!
