\(x=\sqrt[3]{15-3\sqrt{22}}+\sqrt[3]{15+3\sqrt{22}}\)
\(x=\sqrt[3]{15+3\sqrt{22}}+\sqrt[3]{15-3\sqrt{22}}\) tính gt biểu thức \(D=x^3-9x+1981\)
GiáTrị của Biểu thức là:
\(\left(-3\right)\sqrt{2}\sqrt{11}\sqrt{g}\sqrt{t}+3\sqrt{2}\sqrt{11}+2\sqrt{3^3}\sqrt{5}\)
Ta có:\(x=\sqrt[3]{15+3\sqrt{22}}+\sqrt[3]{15-3\sqrt{22}}\Rightarrow x^3=\left(\sqrt[3]{15+3\sqrt{22}}\right)^3+\left(\sqrt[3]{15-3\sqrt{22}}\right)^3+3\sqrt[3]{\left(15+3\sqrt{22}\right)\left(15-3\sqrt{22}\right)}\left(\sqrt[3]{15+3\sqrt{22}}+\sqrt[3]{15-3\sqrt{22}}\right)\)\(\Rightarrow x^3=15+3\sqrt{22}+15-3\sqrt{22}+3\sqrt[3]{27}x\Rightarrow x^3=30+9x\Rightarrow x^3-9x+1981==2011\)
rút gọn P=\(\dfrac{-22+5\sqrt{x}-x}{x+2\sqrt{x}-15}+\dfrac{3\sqrt{x}-1}{\sqrt{x}+5}-\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\left(x\ge0,x\ne9\right)\)
\(P=\dfrac{-x+5\sqrt{x}-22}{x+2\sqrt{x}-15}+\dfrac{3\sqrt{x}-1}{\sqrt{x}+5}-\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\)
\(=\dfrac{-x+5\sqrt{x}-22}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}+\dfrac{3\sqrt{x}-1}{\sqrt{x}+5}-\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\)
\(=\dfrac{-x+5\sqrt{x}-22+\left(3\sqrt{x}-1\right)\left(\sqrt{x}-3\right)-\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}\)
\(=\dfrac{-x+5\sqrt{x}-22+3x-10\sqrt{x}+3-x+25}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}\)
\(=\dfrac{x-5\sqrt{x}+6}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}=\dfrac{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}\)
\(=\dfrac{\sqrt{x}-2}{\sqrt{x}+5}\)
\(\dfrac{8}{\sqrt{5}-1}-\dfrac{22}{4+\sqrt{5}}+\dfrac{\sqrt{15}+2\sqrt{5}}{2+\sqrt{3}}\)
rút gọn giúp mình với
\(\dfrac{8}{\sqrt{5}-1}-\dfrac{22}{4+\sqrt{5}}+\dfrac{\sqrt{15}+2\sqrt{5}}{2+\sqrt{3}}\)
\(=\dfrac{8\left(\sqrt{5}+1\right)}{\left(\sqrt{5}-1\right)\left(\sqrt{5}+1\right)}-\dfrac{22\left(4-\sqrt{5}\right)}{\left(\sqrt{5}+4\right)\left(4-\sqrt{5}\right)}+\dfrac{\sqrt{5}\left(\sqrt{3}+2\right)}{2+\sqrt{3}}\)
\(=\dfrac{8\sqrt{5}+8}{5-1}-\dfrac{88-22\sqrt{5}}{16-5}+\sqrt{5}\)
\(=\dfrac{8\sqrt{5}+8}{4}-\dfrac{88-22\sqrt{5}}{11}+\sqrt{5}\)
\(=2\sqrt{5}+2-8+2\sqrt{5}+\sqrt{5}=5\sqrt{5}-6\)
\(\left(\sqrt{6}-\sqrt{5}\right)^2-\sqrt{11+2\sqrt{30}}\)
\(\sqrt{8+2\sqrt{15}}-\sqrt{8-2\sqrt{15}}\)
\(\sqrt{11+4\sqrt{7}}-\sqrt{14-6\sqrt{5}}\)
\(\sqrt{22-12\sqrt{2}}-\sqrt{19+6\sqrt{2}}\)
\(\sqrt{-6\sqrt{3}+12}+\sqrt{-12\sqrt{3}+21}\)
tớ ko chép lại đề, kí hiệu nhé
(1) \(=\left(\sqrt{6}-\sqrt{5}\right)^2-\sqrt{\left|\sqrt{6}+\sqrt{5}\right|^2}=\left(\sqrt{6}-\sqrt{5}\right)^2-\left(\sqrt{6}+\sqrt{5}\right)=1-2\sqrt{30}-\sqrt{6}-\sqrt{5}\)
ai ra đề mà để đáp án dài thế này mất thẩm mĩ quá!!!
(2) \(=\sqrt{\left|\sqrt{5}+\sqrt{3}\right|^2}-\sqrt{\left|\sqrt{5}-\sqrt{3}\right|^2}=\left(\sqrt{5}+\sqrt{3}\right)-\left(\sqrt{5}-\sqrt{3}\right)=2\sqrt{3}\)
(3) \(=\sqrt{\left|\sqrt{7}+2\right|^2}-\sqrt{\left|3-\sqrt{5}\right|^2}=\sqrt{7}+2-3+\sqrt{5}=\sqrt{7}+\sqrt{5}-1\)
lại thêm 1 phép tính không đẹp....
(4) \(=\sqrt{\left|3\sqrt{2}-2\right|^2}-\sqrt{\left|3\sqrt{2}+1\right|^2}=3\sqrt{2}-2-3\sqrt{2}-1=-3\)
(5) \(=\sqrt{\left|2\sqrt{3}-1\right|^2}+\sqrt{\left|2\sqrt{3}-3\right|^2}=2\sqrt{3}-1+2\sqrt{3}-3=4\sqrt{3}-4\)
kiểm tra lại kết quả nhé ^^! Cảm ơn!
\(\left\{{}\begin{matrix}\frac{2}{\sqrt{x}+1}-\frac{1-x-y}{x+y}=\frac{22}{15}\\\frac{3}{\sqrt{x}+1}+\frac{5+x+y}{x+y}=3\\\\\end{matrix}\right.\)
Đặt: \(\left\{{}\begin{matrix}a=\sqrt{x}+1\\b=x+y\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{2}{a}-\frac{1-b}{b}=\frac{22}{15}\\\frac{3}{a}+\frac{5+b}{b}=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{2}{a}-\frac{1}{b}+1=\frac{22}{15}\\\frac{3}{a}+\frac{5}{b}+1=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{2}{a}-\frac{1}{b}=\frac{7}{15}\\\frac{3}{a}+\frac{5}{b}=2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{6}{a}-\frac{3}{b}=\frac{7}{5}\\\frac{6}{a}+\frac{10}{b}=4\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{6}{a}-\frac{3}{b}=\frac{7}{5}\\\frac{13}{b}=\frac{13}{5}\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a=3\\b=5\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}3=\sqrt{x}+1\\5=x+y\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\sqrt{x}=2\\x+y=5\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=4\\y=5-x=1\end{matrix}\right.\)
Vậy pt có \(n_0\) \(S=\left\{4;1\right\}\)
Cho biểu thức \(G=\frac{-22+5\sqrt{x}-x}{x+2\sqrt{x}-15}+\frac{3\sqrt{x}-1}{\sqrt{x}+5}-\frac{\sqrt{x}-5}{\sqrt{x}-3}\)
a/ Rút gọn G
b/ Tìm tất cả các giá trị của x để G có giá trị nguyên
$x=\root(3)(22\sqrt(2+)25-\root(3)(22\sqrt(2))- 25)$
Đặt \(A=\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}\)
\(\Rightarrow A^3=50-3\sqrt[3]{\left(22\sqrt{2}+25\right)\left(22\sqrt{2}-25\right)}\left(\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}\right)\)
\(\Rightarrow A^3=50-3\sqrt[3]{\left(22\sqrt{2}+25\right)\left(22\sqrt{2}-25\right)}\cdot A\)
\(\Rightarrow A^3=50-3A\sqrt[3]{343}=50-21A\)
\(\Rightarrow A^3+21A-50=0\Leftrightarrow A^3-4A+25A-50=0\)
\(\Leftrightarrow\left(A-2\right)\left(A^2+2A+25\right)=0\)
\(\Leftrightarrow A=2\left(A^2+2A+25>0,\forall A\right)\)
\(\Rightarrow\sqrt[3]{22\sqrt{2}+25}-\sqrt[3]{22\sqrt{2}-25}=2\)
Tick nha bạn 😘
Tính:
a. \(5\sqrt{2}-2\sqrt{48}+6\sqrt{75}-\sqrt{108}\)
b.\(2\sqrt{147}-\dfrac{3}{32}\sqrt{192}+\dfrac{4}{18}\sqrt{243}-\dfrac{1}{10}\sqrt{300}\)
c. \(-\dfrac{1}{2}\sqrt{108}+\dfrac{1}{15}\sqrt{75}-\dfrac{1}{22}\sqrt{363}+\sqrt{12}\)
d. \(\dfrac{5}{8}\sqrt{48}-\dfrac{1}{33}\sqrt{363}+\dfrac{3}{14}\sqrt{147}-\dfrac{1}{4}\sqrt{192}\)
e. \(\dfrac{3}{2}\sqrt{12}+\dfrac{7}{5}\sqrt{75}-\dfrac{9}{10}\sqrt{300}+\dfrac{11}{6}\sqrt{108}\)
a: \(5\sqrt{2}-8\sqrt{3}+30\sqrt{3}-6\sqrt{3}=5\sqrt{2}+16\sqrt{3}\)
b: \(=14\sqrt{3}-\dfrac{3}{32}\cdot8\sqrt{3}+\dfrac{4}{18}\cdot9\sqrt{3}-\dfrac{1}{10}\cdot10\sqrt{3}\)
\(=14\sqrt{3}-\dfrac{3}{4}\sqrt{3}+2\sqrt{3}-1\sqrt{3}=\dfrac{57}{4}\sqrt{3}\)
c: \(=\dfrac{-1}{2}\cdot6\sqrt{3}+\dfrac{1}{15}\cdot5\sqrt{3}-\dfrac{1}{22}\cdot11\sqrt{3}+2\sqrt{3}\)
\(=-3\sqrt{3}+\dfrac{1}{3}\sqrt{3}-\dfrac{1}{2}\sqrt{3}+2\sqrt{3}=-\dfrac{7}{6}\sqrt{3}\)
d: \(=\dfrac{5}{8}\cdot4\sqrt{3}-\dfrac{1}{33}\cdot11\sqrt{3}+\dfrac{3}{14}\cdot7\sqrt{3}-\dfrac{1}{4}\cdot8\sqrt{3}\)
\(=\dfrac{5}{2}\sqrt{3}-\dfrac{1}{3}\sqrt{3}+\dfrac{3}{2}\sqrt{3}-2\sqrt{3}=\dfrac{5}{3}\sqrt{3}\)
giải phương trình :
a, \(\sqrt{x+1}+x+3=\sqrt{1-x}+3\sqrt{1-x^2}\)
b,\(\left(2x-3\right)\sqrt{3+x}+2x\sqrt{3-x}=6x-8+\sqrt{9-x^2}\)
c, \(2x^2-5x+22=5\sqrt{x^3-11x +20}\)
d, \(x^3-3x^2+2\sqrt{\left(x+2\right)^3}=6x\)