Ta có : \(x=2+\sqrt{3}\Rightarrow x-2=\sqrt{3}\Leftrightarrow x^2-4x+4=3\Leftrightarrow x^2-4x+1=0\)
Mặt khác \(x=2+\sqrt{3}\Rightarrow2x-5=2\sqrt{3}-1\)
Khi đó \(A=\frac{\left(x^2-4x+1\right)\left(x^2+2x+10\right)+2x-5}{\sqrt{x^2-4x+1+4}}=\frac{2\sqrt{3}-1}{2}=\sqrt{3}-\frac{1}{2}\)
Giải các phương trình sau:
a) \(x^3-x^2+2x=\sqrt{2x-1}+\sqrt{4x-3}\)
b) \(x^3-x^2+3x+13=4\left(\sqrt{x+3}+\sqrt{3x+1}\right)\)
c) \(x^3-4x^2+6x-1=\sqrt{2x-3}+2\sqrt{x-1}\)
d) \(x^3+4x^2+9x+9=2\sqrt{3x+4}+\sqrt{2x+3}\)
e) \(2x^2-4x+11=2\sqrt{3x-5}+3\sqrt{2x+5}\)
Giải các phương trình sau:
a) \(x^3-x^2+2x=\sqrt{2x-1}+\sqrt{4x-3}\)
b) \(x^3-x^2+3x+13=4\left(\sqrt{x+3}+\sqrt{3x+1}\right)\)
c) \(x^3-4x^2+6x-1=\sqrt{2x-3}+2\sqrt{x-1}\)
d) \(x^3+4x^2+9x+9=2\sqrt{3x+4}+\sqrt{2x+3}\)
e) \(2x^2-4x+11=2\sqrt{3x-5}+3\sqrt{2x+5}\)
Cho
TÍnh
Giải phương trình
1.\(\sqrt{2x-3}-\sqrt{5-2x}=3x^2-12x+14\)
2.\(x^2+2x+15=6\sqrt{4x+5}\)
3.\(x^2-5x-8=2\sqrt{x-2}\)
4.\(\sqrt{x+1+\sqrt{x+\frac{3}{4}}}=x+1\)
Giải phương trình:
a) \(2\sqrt{x^2-4}-3=6\sqrt{x-2}-\sqrt{x+2}\)
b) \(\frac{\sqrt{x-2016}-1}{x-2016}+\frac{\sqrt{y-2017}-1}{y-2017}+\frac{\sqrt{z-2018}-1}{z-2018}=\frac{3}{4}\)
c) \(\sqrt{3+\sqrt{3+x}}=x\)
d) \(\sqrt{6x^2+1}=\sqrt{2x-3}+x^2\)
e) \(\sqrt{x^2+3x+5}+\sqrt{x^2-2x+5}=5\sqrt{x}\)
f) \(\sqrt{x^2+3x}+2\sqrt{x+2}=2x+\sqrt{x+\frac{6}{x}+5}\)
a,\(\sqrt{x^2-5x+4}+\sqrt{x+1}=\sqrt{x-2}+\sqrt{x^2-2x-3}\)
b,\(\sqrt{x^2-3x+2}+\sqrt{x^2-4x+3}=2\sqrt{x^2-5x=4}\)
c,\(\sqrt{4x^2+9x+5}+\sqrt{2x^2+x-1}=\sqrt{x^2-1}\)
a) cho x=\(1+\sqrt[3]{2}\) tính B = \(x^4-2x^5+x^3-3x^2+1942\)
b) cho x = \(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\) tính P =\(\dfrac{x^4-4x^3+x^2+6x+12}{x^2-2x+12}\)
c) cho x = \(1+\sqrt[3]{2}\)\(+\sqrt[3]{4}\) tính C = \(x^5-4x^4+x^3-x^2-2x+2015\)
Giải các phương trình sau:
a) \(x^3-4x^2+8x-4=\sqrt{x-1}+\sqrt{2x+5}\)
b) \(x^2-4x+4=\sqrt{2x+1}+\sqrt{x-3}\)
c) \(2x^2+x+4=2\sqrt{2x+3}+\sqrt{4x-1}\)
d) \(x^3-4x^2+7x-4=2\sqrt{x+2}-\sqrt{3x-2}\)
e) \(x^3-6x^2+14x-8=\sqrt[3]{x+6}+\sqrt{x+2}\)
Cho biểu thức f(x) = x5 - 4x4 -3x3 + 16x2 -38x -8( \(\sqrt{5}\) + 1)
và số a = 2+ \(\sqrt{5}\)
Tính f(a)
