\(A=\sqrt[3]{7+5\sqrt{2}}+\sqrt[3]{7-5\sqrt{2}}\)
\(\Rightarrow A^3=14+3\sqrt[3]{\left(7+5\sqrt{2}\right)\left(7-5\sqrt{2}\right)}\left(\sqrt[3]{7+5\sqrt{2}}+\sqrt[3]{7-5\sqrt{2}}\right)\)
<=>A3=14-3A
<=>A3+3A-14=0
<=>A3-4A+7A-14=0
<=>A.(A-2)(A+2)+7.(A-2)=0
<=>(A-2)(A2+9A-14)=0
<=>A=2(nhận)
Vậy A=2
Rút gọn các biểu thức sau
a. \(\sqrt{3+2\sqrt{2}}-\sqrt{6-4\sqrt{2}}\)
b. \(\sqrt{9-4\sqrt{5}}-\sqrt{5}\)
c. \(\sqrt{23+8\sqrt{7}}-\sqrt{7}\)
Thực hiện các phép tính
a, \(\sqrt{5+2\sqrt{6}}-\sqrt{2-2\sqrt{6}}\)
b,\(\sqrt{7-2\sqrt{10}}-\sqrt{7+2\sqrt{10}}\)
c, \(\sqrt{4-2\sqrt{3}}+\sqrt{4+2\sqrt{3}}\)
d, \(\sqrt{24+8\sqrt{5}+}\sqrt{9-4\sqrt{5}}\)
tính a) \(\sqrt[3]{2-\sqrt{5}}.\left(\sqrt[6]{9+4\sqrt{5}}+\sqrt[3]{2+\sqrt{5}}\right)\)
b) \(\sqrt[4]{17+12\sqrt{2}}-\sqrt{2}\)
c) \(\sqrt[4]{56-24\sqrt{5}}\)
d) \(1+\sqrt[4]{28-16\sqrt{3}}\)
e) \(\frac{2}{\sqrt{4-3\sqrt[4]{5}+2\sqrt{5}-\sqrt[4]{125}}}\)
@Akai Haruma giúp em với chị ơi
Rút gọn:
A=\(\dfrac{\sqrt{a}+2}{\sqrt{a+3}}-\dfrac{5}{a+\sqrt{a}-6}+\dfrac{1}{2-\sqrt{a}}\)
B=\((1-\dfrac{\sqrt{a}}{\sqrt{a}+1})\div(\dfrac{\sqrt{a}+3}{\sqrt{a}-2}+\dfrac{\sqrt{a}+2}{3-\sqrt{a}}+\dfrac{\sqrt{a}+2}{a-5\sqrt{a}+6)}\)
C=\((\dfrac{\sqrt{a}-1}{3\sqrt{a}-1}-\dfrac{1}{3\sqrt{a}+1}+\dfrac{8\sqrt{a}}{9a-1})\div(1-\dfrac{3\sqrt{a}-2}{3\sqrt{a}+1)}\)
Giups mình cái mình đag cần gấp
Rút gọn;
A=\(\sqrt{a+\sqrt{a+\dfrac{1}{2}+\sqrt{a+\dfrac{1}{4}}}}\)
B=\(\dfrac{1+2a}{1+\sqrt{1+2a}}+\dfrac{1-2a}{1-\sqrt{1-2a}}\)
Rút gọn B=\(\frac{\sqrt{x}+3}{\sqrt{x}+1}+\frac{2}{\sqrt{x}-3}-\frac{7\sqrt{x}-13}{x-2\sqrt{x}-3}\)
1. giải phương trình
a. \(\sqrt{x+4}=3\)
b. \(\sqrt{x-1}-\sqrt{9x-9}+2\sqrt{36x-36}=2+\sqrt{25x-25}\)
c. \(\sqrt{4x-20}+\sqrt{x-5}-\dfrac{1}{3}\cdot\sqrt{9x-45}=4\)
d.\(\sqrt{x^2-10x+25}=x-3\)
e. \(\sqrt{x^2-4x+4}=2\)
Cho a, b, c. CMR:
\(\sqrt[3]{\left(\frac{2a}{b+c}\right)^2}+\sqrt[3]{\left(\frac{2b}{c+a}\right)^2}+\sqrt[3]{\left(\frac{2c}{a+b}\right)^2}\ge3\)
Giải pt sau bằng phương pháp đặt ẩn phụ
a)\(3\sqrt{x^2+3x}\)=(x+5)(2-x)
b)\(\sqrt{5x^2+10x+1}\)=7-x^2-2x