Rút gọn biểu thức sau:
\(\sqrt{\left(\sqrt{18}+\sqrt{14}\right).\sqrt{8-3\sqrt{7}}}\)
rút gọn
a) \(\frac{7\sqrt{2}+2\sqrt{7}}{\sqrt{14}}-\frac{5}{\sqrt{7}+\sqrt{5}}\)
b) \(\frac{\sqrt{2}\left(3+\sqrt{5}\right)}{2\sqrt{2}+\sqrt{3+\sqrt{5}}}+\frac{\sqrt{2}\left(3-\sqrt{5}\right)}{2\sqrt{2}-\sqrt{3-\sqrt{5}}}\)
c) \(\sqrt[3]{16-8\sqrt{5}}+\sqrt[3]{16\text{ }+8\sqrt{5}}\)
helppp mee
giải pt :
a) \(\sqrt{x-1}+\sqrt{x^3+x^2+x+1}=1+\sqrt{x^4-1}\)
b0 \(4\sqrt{x+1}=x^2-5x+14\)
c) \(2x+3\sqrt{4-5x}+\sqrt{x+2}=8\)
d) \(\dfrac{x^2+x}{\sqrt{x^2+x+1}}=\dfrac{2-x}{\sqrt{x-1}}\)
\(\sqrt{49x-98}-14\sqrt{\frac{x-2}{49}=}3\sqrt{x-2}+8\)
Rút gọn
Tính:
\(a.\) \(A=\sqrt{12}-2\sqrt{48}+\dfrac{7}{5}\sqrt{75}\)
\(b.\) \(B=\sqrt{14-6\sqrt{5}}+\sqrt{\left(2-\sqrt{5}\right)^2}\)
\(c.\) \(C=\left(\sqrt{6}-\sqrt{2}\right)\sqrt{2+\sqrt{3}}\)
\(d.\) \(D=\dfrac{5+\sqrt{5}}{\sqrt{5}+2}+\dfrac{\sqrt{5}-5}{\sqrt{5}}-\dfrac{11}{2\sqrt{5}+3}\)
1) Tính
a) \(\sqrt{14+6\sqrt{5}}-\sqrt{\dfrac{\sqrt{5}-2}{\sqrt{5}+2}}\)
b) \(\dfrac{2\left(\sqrt{2}-\sqrt{6}\right)}{3\sqrt{2}-\sqrt{3}}\)
2) giải phương trình
\(\sqrt{4x+8}+\sqrt{9x+18}-\sqrt{9}=\sqrt{16x+32}\)
tìm x biết:
a. \(\sqrt{9x^2-6x+1}=\sqrt{x^2+8x+16}\)
b. \(\sqrt{x+3+14\sqrt{x-1}}+\sqrt{x+8-6\sqrt{x-1}}=5\)
Tính giá trị của biểu thức: \(M=\dfrac{1+ab}{a+b}-\dfrac{1-ab}{a-b}\) với \(b=\dfrac{3\sqrt{8}-2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}\); \(a=\sqrt{4+\sqrt{8}}.\sqrt{2+\sqrt{2+\sqrt{2}}}.\sqrt{2-\sqrt{2+\sqrt{2}}}\)
rút gọn: \(\left(\sqrt{28}-2\sqrt{14}+\sqrt{7}\right)\sqrt{7}+7\sqrt{8}\)