`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
\(\sqrt{0}=0\)
`b)`
\(\sqrt{64}=8\)
`c)`
\(\sqrt{\dfrac{9}{16}}=\dfrac{3}{4}\)
`d)`
\(\sqrt{0,04}=0,2\)
`2,`
`a)`
`12^2 = 144`
`=> \sqrt {144} = 12`
`b)`
`-(0,36)^2 = -0,1296`
`=> -\sqrt {0,1296} = -0,36`
`c)`
`(2 \sqrt {2/7})^2 = 8/7`
`=> \sqrt {8/7} = 2 \sqrt {2/7}`
`d)`
`( (0,2)/(\sqrt {3}) )^2 = 1/75`
`=> \sqrt {1/75} = (0,2)/(\sqrt {3})`
`3,`
`a.`
`\sqrt {5^2 - 4^2} = \sqrt {25 - 16} = \sqrt {9} = 3`
`b,`
`\sqrt {25^2 - 24^2}`
`= \sqrt {625 - 576}`
`= \sqrt {49}`
`= 7`
`c.`
`\sqrt {85^2 - 84^2}`
`= \sqrt {7225 - 7056}`
`= \sqrt {169}`
`= 13`
`d.`
`\sqrt {26^2 - 24^2}`
`= \sqrt {676 - 576}`
`= \sqrt {100}`
`= 10`
`4,`
`a.`
`A = \sqrt {49} + \sqrt {25} - 4\sqrt {0,25}`
`= 7 + 5 - 4*0,5`
`= 7 + 5 - 2`
`= 12 - 2`
`= 10`
Vậy, `A=10`
`b.`
`B = ( \sqrt {169} - \sqrt [121} - \sqrt {81}) \div \sqrt {0,49}`
`= (13 - 11 - 9) \div 0,7`
`= -7 \div 0,7`
`= -10`
Vậy. `B=-10`
`c.`
`C = \sqrt {1,44} + 3 \sqrt {1,69}`
`= 1,2 + 3*1,3`
`= 1,2 + 3,9`
`= 5,1`
Vậy, `C=5,1`
`d.`
`D = \sqrt {0,04} + 2\sqrt {0,25}`
`= 0,2 + 2*0,5`
`= 0,2+1`
`= 1,2`
Vậy, `D=1,2`
`e.`
`E = \sqrt {1/9}* \sqrt {0,81} * \sqrt {0,09}`
`= 1/3*0,9*0,3`
`= 0,09`
Vậy, `E=0,09`
`f.`
`F = 3/5 \sqrt {16} + 2 \sqrt {16/25}`
`= 3/5*4 + 2* 4/5`
`= 12/5 + 8/5`
`= 4`
Vậy, `F=4`
`@` `\text {Kaizuu lv u}`
Bài 4:
\(a,A=\sqrt{49}+\sqrt{25}-4\sqrt{0,25}=\sqrt{7^2}+\sqrt{5^2}-4.\sqrt{\left(0,5\right)^2}=7+5+4.0,5=14\\ b,B=\left(\sqrt{169}-\sqrt{121}-\sqrt{81}\right):\sqrt{0,49}=\left(\sqrt{13^2}-\sqrt{11^2}-\sqrt{9^2}\right):\sqrt{\left(0,7\right)^2}=\left(13-11-9\right):0,7=-7:0,7=-10\\ c,C=\sqrt{1,44}+3\sqrt{1,69}=\sqrt{\left(1,2\right)^2}+3\sqrt{\left(1,3\right)^2}=1,2+3.1,3=5,1\)
Bài 4:
\(d,D=\sqrt{0,04}+2.\sqrt{0,25}=\sqrt{\left(0,2\right)^2}+2.\sqrt{\left(0,5\right)^2}=0,2+2.0,5=1,2\\ e,E=\sqrt{\dfrac{1}{9}}.\sqrt{0,81}.\sqrt{0,09}=\sqrt{\left(\dfrac{1}{3}\right)^2}.\sqrt{\left(0,9\right)^2}.\sqrt{\left(0,3\right)^2}=\dfrac{1}{3}.0,9.0,3=0,09\\ f,F=\dfrac{3}{5}\sqrt{16}+2.\sqrt{\dfrac{16}{25}}=\dfrac{3}{5}.\sqrt{4^2}+2.\sqrt{\left(\dfrac{4}{5}\right)^2}=\dfrac{3}{5}.4+2.\dfrac{4}{5}=\dfrac{12}{5}+\dfrac{8}{5}=\dfrac{20}{5}=4\)
