a) Ta có:
\(\sqrt{0,09.64}=\sqrt{0,09}.\sqrt{64}\)
\(=\sqrt{(0,3)^2}.\sqrt{8^2}\)
\(=|0,3|. |8|\)
\(=0,3.8\)
\(=2,4\).
b) Ta có:
\(\sqrt{2^{4}.(-7)^{2}}=\sqrt{2^4}.\sqrt{(-7)^2}\)
\(=\sqrt{(2^2)^2}.\sqrt{(-7)^2}\)
\(=\sqrt{4^2}.\left| -7 \right| \)
\(=|4|.|-7|\)
\(=4.7\)
\(=28\).
c) Ta có:
\(\sqrt{12,1.360}=\sqrt{12,1.(10.36)}\)
\(=\sqrt{(12,1.10).36}\)
\(=\sqrt{121.36}\)
\(=\sqrt{121}.\sqrt{36}\)
\(=\sqrt{11^2}.\sqrt{6^2}\)
\(=|11|.|6|\)
\(=11.6\)
\(=66\).
d) Ta có:
\(\sqrt{2^{2}.3^{4}}=\sqrt{2^2}.\sqrt{3^4}\)
\(=\sqrt{2^{2}}.\sqrt{(3^2)^2}\)
\(=\sqrt{ 2^2}.\sqrt{9^2}\)
\(=|2|.|9|\)
\(=2.9\)
\(=18\).
