Bài 1:
1) \(\sqrt{81\cdot196}=\sqrt{81}\cdot\sqrt{196}=9\cdot14=126\)
2) \(\sqrt{360\cdot250}=\sqrt{36\cdot25\cdot100}=\sqrt{36}\cdot\sqrt{25}\cdot\sqrt{100}=6\cdot5\cdot10=300\)
3)\(\sqrt{0.016\cdot6.4\cdot100}=\sqrt{0.16\cdot0.64\cdot100}=\sqrt{0.16}\cdot\sqrt{0.64}\cdot\sqrt{100}=0.4\cdot0.8\cdot10=3.2\)4)\(\sqrt{14.4\cdot490}=\sqrt{144\cdot49}=\sqrt{144}\sqrt{49}=12\cdot7=84\)
5)\(\sqrt{0.9\cdot1.21\cdot1000}=\sqrt{0.09}\sqrt{1.21}\sqrt{100}=0.3\cdot1.1\cdot10=3.3\)
6)\(\sqrt{75\cdot180}=\sqrt{75}\sqrt{180}=5\sqrt{3}\cdot6\sqrt{5}=30\sqrt{15}\)
7)\(\sqrt{117^2-108^2}=\sqrt{\left(117-108\right)\left(117+108\right)}=\sqrt{9\cdot225}=\sqrt{9}\sqrt{225}=3\cdot15=45\)
8)\(\sqrt{221^2-220^2}=\sqrt{\left(221-220\right)\left(221+220\right)}=\sqrt{1\cdot441}=21\)
9)\(\sqrt{3\dfrac{1}{16}\cdot2\dfrac{14}{25}\cdot2\dfrac{34}{81}}=\sqrt{\dfrac{49}{16}}\cdot\sqrt{\dfrac{64}{25}}\cdot\sqrt{\dfrac{196}{81}}=\dfrac{7}{4}\cdot\dfrac{8}{5}\cdot\dfrac{14}{9}=\dfrac{196}{45}\)
10)\(\sqrt{65^2-63^2}=\sqrt{\left(65-63\right)\left(65+63\right)}=\sqrt{2\cdot128}=\sqrt{256}=16\)
Tick nha bạn 😘
các bn ơi giúp mink bài 2 đề đầu vs ạ. Mik cảm ơn trc
