\(\dfrac{26}{2\sqrt{3}+5}=\dfrac{26\left(2\sqrt{3}-5\right)}{\left(2\sqrt{3}\right)^2-5^2}=\dfrac{26\left(2\sqrt{3}-5\right)}{-13}=-2\left(2\sqrt{3}-5\right)=10-4\sqrt{3}\)
Thuc hien phep tinh: B=\(\dfrac{2+\sqrt{3}}{\sqrt{2}+\sqrt{2+\sqrt{2}}}+\dfrac{2-\sqrt{3}}{\sqrt{2}-\sqrt{2-\sqrt{3}}}\)
cho bieu thuc A=\(\left(\dfrac{6x+4}{3\sqrt{3x^3}-8}-\dfrac{\sqrt{3x}}{3x+2\sqrt{3x}+4}\right)\left(\dfrac{1+3\sqrt{3x^3}}{1+\sqrt{3x}}-\sqrt{3x}\right)\)
a.rut gon bieu thuc A
b. tim cac gia tri nguyen x de A nguyen
(\(\dfrac{1}{\sqrt{x}-\sqrt{x-1}}-\dfrac{x-3}{\sqrt{x-1}-\sqrt{2}})\left(\dfrac{2}{2-\sqrt{x}}-\dfrac{\sqrt{x}+\sqrt{2}}{2\sqrt{x}-x}\right)\)
Rut gon bieu thuc
Voi gia tri nao cua x thi can thuc sau co nghia : \(\sqrt{\dfrac{-2}{x+1}}\)
moi nguoi giup minh cau nay voi , minh cam on!!
cho bieu thuc P=(\(\dfrac{1}{x+2\sqrt{x}}-\dfrac{1}{\sqrt{x}+2}\)): \(\dfrac{1-\sqrt{x}}{x+4\sqrt{x}+4}\) (với x>0, x khác 1)
a. rut gon bieu thuc P
b. Tìm x để P=\(\dfrac{4}{3}\)
1,thu gon bieu thuc
a A=\(\dfrac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}\)
b,B=\(\dfrac{12\sqrt{6}}{\sqrt{7+2\sqrt{6}-\sqrt{7-2\sqrt{6}}}}\)
c, C=\(\dfrac{\sqrt{c^2+2c+1}}{\left|c\right|-1}\)
2,giai cac phuong trinh
a,\(x^2-9\sqrt{x}+14=0\)
b, \(\sqrt{3x^2-18x+28}+\sqrt{4x^2-24x+45}=-5-x^2+6\)
GIUP MINH VOI MINH CAN GAP
Rút gọn biểu thức \(P=\dfrac{x\sqrt{x}+26\sqrt{x}-19}{x+2\sqrt{x}-3}-\dfrac{2\sqrt{x}}{\sqrt{x}-1}+\dfrac{\sqrt{x}-3}{\sqrt{x}+3}\)
Cho cac bieu thuc :
\(A=\dfrac{\sqrt{x}+4}{\sqrt{x}+2},B=\left(\dfrac{\sqrt{x}}{\sqrt{x}+4}+\dfrac{4}{\sqrt{x}-4}\right):\dfrac{x+16}{\sqrt{x}+2}\)
a) Rut gon B ?
b) Tim cac gia tri nguyen cua x de cac gia tri cua bieu thuc B(A-1) la so nguyen.
Tính giá trị các biểu thức:
a/ \(\sqrt{7+\sqrt{7^2-4}}-\sqrt{7-\sqrt{7^2-4}}\)
b/ \(2\sqrt{40\sqrt{12}}-2\sqrt{\sqrt{75}}-3\sqrt{5\sqrt{48}}\)
c/ \(\left(\dfrac{1}{2+\sqrt{3}}-\dfrac{12}{3+\sqrt{3}}+\dfrac{26}{4-\sqrt{3}}\right)\cdot\left(4-3\sqrt{3}\right)\)
