\(A=\dfrac{\sqrt{8}-\sqrt{7}}{8-7}+\sqrt{25\times7}-2\sqrt{2}\\ =\sqrt{8}-\sqrt{7}+5\sqrt{7}-2\sqrt{2}\\ =2\sqrt{2}-\sqrt{7}+5\sqrt{7}-2\sqrt{2}\\ =4\sqrt{7}\)
1) rút gọn
A= \(3\sqrt{2}+5\sqrt{8}-2\sqrt{50}\)
B= \(\dfrac{1}{3+\sqrt{5}}+\dfrac{1}{3-\sqrt{5}}\)
C= \(\sqrt{7-4\sqrt{3}}+\sqrt{12+6\sqrt{3}}\)
Giúp mk vs ạ mk cần gấp
Rút gọn các biểu thức sau:
a. \(\dfrac{8}{\left(\sqrt{5}+\sqrt{3}\right)^2}\) - \(\dfrac{8}{\left(\sqrt{5}-\sqrt{3}\right)^2}\)
b.\(\dfrac{1}{4-3\sqrt{2}}\) - \(\dfrac{1}{4+3\sqrt{2}}\)
c.\(\left(\dfrac{\sqrt{7}+3}{\sqrt{7}-3}-\dfrac{\sqrt{7}-3}{\sqrt{7}+3}\right)\): \(\sqrt{28}\)
d.\(\dfrac{3}{\sqrt{6}-\sqrt{3}}\)+\(\dfrac{4}{\sqrt{7}+\sqrt{3}}\)
Rút gọn: \(M=\dfrac{8}{\sqrt{5}-\sqrt{3}}+\dfrac{7}{\sqrt{3}-2}+\dfrac{4}{\sqrt{2}-1}+\dfrac{3\sqrt{5}-\sqrt{15}}{\sqrt{15}}\)
P = (\(\dfrac{2\sqrt{x}}{\sqrt{x}}-\dfrac{x-4}{\sqrt{x}+2}\)). \(\dfrac{1}{\sqrt{x}-2}\)
a Tìm đkxđ rồi rút gọn P
b Tìm x để P = \(\dfrac{2}{3}\)
c Tính p khi x = 8\(-\)2\(\sqrt{7}\)
Thực hiện phép tính ( rút gọn biểu thức )
a) \(\dfrac{1}{2\sqrt{2}-3}\)+\(\dfrac{1}{2\sqrt{2}+3}\) b) \(\dfrac{\sqrt{2}}{2\sqrt{2}+\sqrt{7}}\)+\(\dfrac{\sqrt{2}}{2\sqrt{2}-\sqrt{7}}\)
c) \(\dfrac{1}{2-\sqrt{5}}\)-\(\dfrac{2}{2+\sqrt{5}}\)
Rút gọn:
\(A=\sqrt{63}-2\sqrt{175}+\sqrt{252}-\frac{1}{7}\sqrt{28}\)
Rút gọn các biểu thức sau :
a) \(\sqrt{18\left(\sqrt{2}-\sqrt{3}\right)^2}\) - \(\sqrt{54}\)
b) \(\dfrac{a+\sqrt{ab}}{\sqrt{a}-\sqrt{b}}\) - a\(\sqrt{\dfrac{1}{a}}\)
c) ( \(\sqrt{28}\) - 2\(\sqrt{3}\) +7) \(\sqrt{7}\) +\(\sqrt{84}\)
rút gọn biểu thức sau :
a. \(A=\dfrac{x^2-\sqrt{x}}{x+\sqrt{x}+1}-\dfrac{2x+\sqrt{x}}{\sqrt{x}}+\dfrac{2\left(x-1\right)}{\sqrt{x}-1}\)
b. \(B=7:\left(a+b\right)+8:\left(a-b\right)-16b:\left(a^2-b^2\right)\)
A= \(\dfrac{3}{\sqrt{7}-2}\) + \(\sqrt{\left(\sqrt{7}-3\right)}^2\)
B= \(\left(\dfrac{\sqrt{x}}{\sqrt{x}-1}-\dfrac{\sqrt{x}}{x-\sqrt{x}}\right)\):\(\left(\dfrac{\sqrt{x}+1}{x-1}\right)\)
Rút gọn A,B
