\(i,\sqrt{12,1.360}=\sqrt{12,1}.6\sqrt{10}=6.\sqrt{12,1.10}=6.\sqrt{121}=6.\sqrt{11^2}=6.11=66\)

\(k,\sqrt{0,4}.\sqrt{6,4}=\sqrt{0,4.6,4}=\sqrt{\dfrac{64}{25}}=\dfrac{\sqrt{8^2}}{\sqrt{5^2}}=\dfrac{8}{5}\)

\(l,-0,4.\sqrt{\left(-0,4\right)^2}=-0,4.0,4=-0,16\)

\(m,\sqrt{2^4.\left(-7\right)^2}=\sqrt{4^2}.\sqrt{\left(-7\right)^2}=4.7=28\)

i, \(\sqrt{12,1\cdot360}=\sqrt{4356}=\sqrt{66^2}=66\)

k, \(\sqrt{0,4}.\sqrt{6,4}=\sqrt{0,4\cdot6,4}=\sqrt{\dfrac{64}{25}}=\sqrt{\dfrac{2^6}{5^2}}=\dfrac{2^3}{5}=\dfrac{8}{5}\)

l, \(-0,4\sqrt{\left(-0,4\right)^2}=-0,4\cdot\left|-0,4\right|=-0,4\cdot0,4=-\dfrac{4}{25}\)

m, \(\sqrt{2^4\cdot\left(-7\right)^2}=2^2\cdot\left|-7\right|=4\cdot7=28\)

i)        \(\sqrt{12,1.360}=\sqrt{12,1}.\sqrt{360}=\sqrt{12,1}.\sqrt{36}.\sqrt{10}=\left(\sqrt{12,1}.\sqrt{10}\right)\sqrt{36}=\sqrt{121}.\sqrt{36}=11.6=66\)

k)       \(\sqrt{0,4}.\sqrt{6,4}=\sqrt{0,4.6,4}=\sqrt{2,56}=1,6\)

l)        \(-0,4\sqrt{\left(-0,4\right)^2}=-0,4\left|-0,4\right|=-0,4.0,4=0,16\)

m)         \(\sqrt{2^4.\left(-7\right)^2}=\sqrt{2^2.2^2.\left(-7\right)^2}=\left|2.2.7\right|=28\)

a)1/10

b)3/10

c)-13/10

d)-4/25

Rất tiếc! Bạn Freya làm sai rồi...

tính thành căn hay p/ số hay giải nghiệm

Lời giải:

\(\sqrt[-0,4]{(-0,4)^2}=\sqrt[-0,4]{\frac{4}{25}}=(\frac{4}{25})^{\frac{1}{-0,4}}=(\frac{4}{25})^{\frac{-5}{2}}=\frac{1}{(\frac{4}{25})^{\frac{5}{2}}}=\frac{1}{\sqrt{(\frac{4}{25})^5}}=\frac{1}{(\frac{2}{5})^5}=\frac{3125}{32}\)

\(\sqrt[-0.4]{\left(-0.4\right)^2}=\sqrt[-0.4]{\dfrac{4}{25}}=\left(\dfrac{4}{25}\right)^{\dfrac{1}{-0.4}}=\dfrac{3125}{32}\)

a, 0,1

b,0,3

c,-1,3

d,-0,16

ta có : \(\left(\sqrt{8}-3\sqrt{2}+\sqrt{10}\right)\left(\sqrt{2}-3\sqrt{0,4}\right)\)

\(=\left(\sqrt{10}-\sqrt{2}\right)\left(\sqrt{2}-\dfrac{3\sqrt{10}}{5}\right)\)

\(=2\sqrt{5}-6-2+\dfrac{6\sqrt{5}}{5}=\dfrac{16}{5}\sqrt{5}-8\)

Mysterious Person giup mk

\(=5\cdot\left(\dfrac{2}{5}-\dfrac{13}{12}\right):\left[-8\cdot\dfrac{11}{8}\right]\)

\(=5\cdot\dfrac{-41}{60}\cdot\dfrac{-1}{11}=\dfrac{205}{60\cdot11}=\dfrac{41}{132}\)

= 5. (0,4 - 13/12) : -11

= 5. -41/60 : -11

=-41/132

\(A=\frac{2}{7}\)

\(A=\frac{\left(0,4-\frac{2}{\sqrt{81}}+\frac{2}{11}\right)}{1,4-\frac{7}{\sqrt{81}}+\frac{7}{11}}=\frac{2\left(0,2-\frac{1}{\sqrt{81}}+\frac{1}{11}\right)}{7\left(0,2-\frac{1}{\sqrt{81}}+\frac{1}{11}\right)}=\frac{2}{7}\)

Ta có: A=\(\frac{\left(0,4-\frac{2}{\sqrt{81}}+\frac{2}{11}\right)}{\left(1,4-\frac{7}{\sqrt{81}}+\frac{7}{11}\right)}\)

            =\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}\)

            =\(\frac{2.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}\)

       => A=\(\frac{2}{7}\)

                                                            Bài giải

\(\left|\sqrt{x+1}-0,5\right|-0,6=\sqrt{\left(-3\right)^2}+0,4\)

\(\left|\sqrt{x+1}-0,5\right|-0,6=3+0,4\)

\(\left|\sqrt{x+1}-0,5\right|-0,6=3,4\)

\(\left|\sqrt{x+1}-0,5\right|=3,4+0,6\)

\(\left|\sqrt{x+1}-0,5\right|=4\)

\(\Rightarrow\orbr{\begin{cases}\sqrt{x+1}-0,5=-4\\\sqrt{x+1}-0,5=4\end{cases}\Rightarrow}\orbr{\begin{cases}\sqrt{x+1}=-3,5\text{ ( loại ) }\\\sqrt{x+1}=4,5\end{cases}}\Rightarrow\text{ }x+1=20,25\text{ }\Rightarrow\text{ }x=19,25\)

\(\Rightarrow\text{ }x=19,25\)

Ta có: \(|\sqrt{x+1}-0,5|=4\)\(\left(ĐK:x\ge-1\right)\)

   <=> \(\orbr{\begin{cases}\sqrt{x+1}-0,5=4\\\sqrt{x+1}-0,5=-4\end{cases}}\)

   <=> \(\orbr{\begin{cases}x=19,25\\x\in\varnothing\end{cases}}\)