Lời giải:
Đặt \(\sqrt[3]{2}=a\Rightarrow a^3=2\Rightarrow 1=a^3-1\)
Khi đó:
\(x=\sqrt[3]{1-3\sqrt[3]{4}+3\sqrt[3]{2}}=\sqrt[3]{a^3-1-3a^2+3a}\)
\(=\sqrt[3]{a^3-3a^2+3a-1}=\sqrt[3]{(a-1)^3}=a-1=\sqrt[3]{2}-1\)
1.\(\sqrt{-4x^2+25}=x\)
2.\(\sqrt{3x^2-4x+3}=1-2x\)
3. \(\sqrt{4\left(1-x\right)^2}-\sqrt{3}=0\)
4.\(\dfrac{3\sqrt{x+5}}{\sqrt{ }x-1}< 0\)
5. \(\dfrac{3\sqrt{x-5}}{\sqrt{x+1}}\ge0\)
Gidipt 1) sqrt(x ^ 2 - x) = sqrt(3 - x)
2) sqrt(x ^ 2 - 4x + 3) = x - 2
3) sqrt(4 * (1 - x) ^ 2) - 6 = 0
4) sqrt(x ^ 2 - 4x + 4) = sqrt(4x ^ 2 - 12x + 9)
5) sqrt(x ^ 2 - 4) + sqrt(x ^ 2 + 4x + 4) = 0
6) 1sqrt(x + 2sqrt(x - 1)) + sqrt(x - 2sqrt(x - 1)) = 2
tính:
a,\(\sqrt{9-4\sqrt{5}}-\sqrt{5}\)
b,\(\sqrt{7-4\sqrt{3}}+\sqrt{4-2\sqrt{3}}\)
c,\(\dfrac{x-49}{\sqrt{x}-7}\)
d,\(\sqrt{4+2\sqrt{3}}-\sqrt{13+4\sqrt{3}}\)
e,\(2+\sqrt{17-4\sqrt{9+4\sqrt{45}}}\)
Tính:
\(\left(\dfrac{3\sqrt{3}-2\sqrt{2}}{\sqrt{3}-\sqrt{2}}+\dfrac{3\sqrt{2}+2\sqrt{3}}{\sqrt{3}+\sqrt{2}}\right)\cdot\dfrac{5-2\sqrt{6}}{4}\)
Rút gọn:
\(\sqrt{4+2\sqrt{3}}+\sqrt{4-2\sqrt{3}}-\frac{5}{\sqrt{3}-2\sqrt{2}}-\frac{5}{\sqrt{3}+\sqrt{8}}\)
Giải các phường trình sau:
1) \(\sqrt{2x-1}=\sqrt{5}\)
2) \(\sqrt{3}x^2-\sqrt{12}=0\)
3) \(\sqrt{x-5}=3\)
4) \(\sqrt{4x^2}-6\)
5) \(\sqrt{\left(x-3\right)^2}=9\)
6) \(\sqrt{4\left(1-x\right)^2}-6=0\)
7) \(\sqrt{9\left(x-1\right)}=21\)
8) \(\sqrt[3]{x+1}=2\)
9) \(\sqrt{4x^2+4x+1}=6\)
10) \(\sqrt{2}x-\sqrt{50}=0\)
11) \(\sqrt{\left(2x-1\right)^2}=3\)
12) \(\sqrt[3]{3-2x}=-2\)
Mọi người ơi giúp em với!!! :((((
Rút gọn :
\(\dfrac{\sqrt{x+\sqrt{4\left(x-1\right)}}-\sqrt{x-\sqrt{4\left(x-1\right)}}}{\sqrt{x^2-4\left(x-1\right)}}.\left(\sqrt{x-1}-\dfrac{1}{\sqrt{x-1}}\right)\)
b)\(\left(\sqrt{2}+1\right)\left(\sqrt{3}+1\right)\left(\sqrt{6}+1\right)\left(5-2\sqrt{2}-\sqrt{3}\right)\)
c)\(\left(\sqrt{5}+1\right)\left(\sqrt{7}+1\right)\left(\sqrt{35}+1\right)\left(34-4\sqrt{7}-6\sqrt{5}\right)\)
d) \(\left(\sqrt{7}+1\right)\left(2\sqrt{2}-1\right)\left(2\sqrt{14}-1\right)\left(55+12\sqrt{2}-7\sqrt{7}\right)\)
e)\(\left(3\sqrt{2}+1\right)\left(2\sqrt{3}+1\right)\left(6\sqrt{6}+1\right)\left(215-34\sqrt{3}-33\sqrt{2}\right)\)
bài 1) rút gọn
1) 5√\(\frac{1}{5}\) 2)\(\frac{12}{5}\)√\(\frac{5}{4}\) 3)\(\frac{30}{5\sqrt{6}}\) 4) \(\frac{20}{2\sqrt{5}}\) 5)\(\frac{2-\sqrt{2}}{\sqrt{2}}\) 6) \(\frac{11+\sqrt{11}}{1+\sqrt{ }11}\) 7) \(\frac{\sqrt{21-\sqrt{7}}}{1-\sqrt{3}}\) 8)\(\frac{\sqrt{2+\sqrt{3}}}{2+\sqrt{6}}\) 9)\(\frac{\sqrt{10-\sqrt{2}}}{\sqrt{5-}1}\) 10)\(\frac{2\sqrt{3}-3\sqrt{2}}{\sqrt{3}-\sqrt[]{2}}\)
bài 2) với các biểu thức đã cho là có nghĩa và rút gọn
1)\(\frac{x-\sqrt{x}}{\sqrt{x}-1}\) 2)\(\frac{x\sqrt{x}-2x}{2-\sqrt{x}}\) 3) \(\frac{x\sqrt{y}-y\sqrt{x}}{\sqrt{x}-\sqrt{y}}\) 4) \(\frac{a\sqrt{b}-\sqrt{a}}{\sqrt{b}-b\sqrt{a}}\) 5) \(\frac{a-1}{\sqrt{a}+1}\) 6) \(\frac{4-x}{2\sqrt{x}-x}\) 7)\(\frac{a+1+2\sqrt{a}}{1+\sqrt{a}}\) 8)\(\frac{3\sqrt{x}-x}{3+2\sqrt{3x}-x}\) 9)\(\frac{y+12-4\sqrt{3y}}{y-12}\) 10)\(\frac{4\sqrt{x}-x-4}{x-4}\) 11)\(\frac{x+y-2\sqrt{xy}}{x\sqrt{y}-y\sqrt{x}}\)
Câu1: Rút gọn
\(a,x+\sqrt{\left(x+2\right)^2}\cdot\left(x-2\right)\\ b,\sqrt{m^2-6m+9-2m}\left(x>3\right)\\ c,1+\sqrt{\frac{\left(x-1\right)^2}{x-1}}\\ d,\sqrt{x+4\sqrt{x-4}}+\sqrt{x-4\sqrt{x-4}}\)
Câu 2: So sánh
\(a,3và\sqrt{5}\\ \\ \\ b,2\sqrt{2}và3\sqrt{2}\\ \\ \\ c,-4\sqrt{5}và-6\sqrt{6}\\ \\ \\ d,2\sqrt{3}-5và\sqrt{3}-4\\ \\ \\e,A=\sqrt{2006}-\sqrt{2005}và\\ B=\sqrt{2005}-\sqrt{2004}\)
Câu 3: Rút gọn
\(a,\sqrt{16-2\sqrt{55}}\\ \\ \\ \\ \\ \\ \\ \\ \\ b,\sqrt{14-6\sqrt{5}}\\ \\ \\ \\ \\ \\ \\ \\ \\ c,\sqrt{36+12\sqrt{5}}\\ \\ \\ \\ \\ \\ \\ \\ \\ d,\sqrt{29+12\sqrt{5}}\)
Câu4: Tìm đkxđ
\(a,\sqrt{x^2-9}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ b,\sqrt{x^2-3x+2}\)
\(c,\frac{\sqrt{x+3}}{\sqrt{5-x}}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ d,\sqrt{\frac{x+3}{5-x}}\)
Chứng minh:
a) (\(\sqrt{3}-1\))\(^2\) = \(4-2\sqrt{3}\)
b) \(\sqrt{4-2\sqrt{ }3}-\sqrt{3=-1}\)
Thực hiện phép tính
a, \(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}\)
b, \(\sqrt{5-\sqrt{13+4\sqrt{3}}}+\sqrt{3+\sqrt{13+4\sqrt{3}}}\)
c, \(\sqrt{1+\sqrt{3+\sqrt{13+4\sqrt{3}}}}+\sqrt{1-\sqrt{3-\sqrt{13-4\sqrt{3}}}}\)
d, \(\left(\sqrt{3}-\sqrt{2}\right)\sqrt{5+2\sqrt{6}}\)