\(\dfrac{1}{x}+\dfrac{1}{\left(x+1\right)^2}=15\)
\(\Rightarrow\dfrac{x^2+2x+1}{x\left(x+1\right)^2}+\dfrac{x}{x\left(x+1\right)^2}=15\)
\(\Rightarrow\dfrac{x^2+3x+1}{x\left(x+1\right)^2}=15\)
\(\Rightarrow x^2+3x+1=15x\left(x^2+2x+1\right)\)
\(\Rightarrow x^2+3x+1=15x^3+30x^2+15x\)
\(\Rightarrow15x^3+29x^2+12x+1=0\)
Phân tích thành nhân tử là tìm được x :)))
Giải các phương trình:
a) \(\dfrac{\left(x+3\right)\left(x-3\right)}{3}+2=x\left(1-x\right);\) b) \(\dfrac{x+2}{x-5}+3=\dfrac{6}{2-x};\)
c) \(\dfrac{4}{x+1}=\dfrac{-x^2-x+2}{\left(x+1\right)\left(x+2\right)}.\)
Giải các phương trình :
a) \(\dfrac{12}{x-1}-\dfrac{8}{x+1}=1\)
b) \(\dfrac{16}{x-3}+\dfrac{30}{1-x}=3\)
c) \(\dfrac{x^2-3x+5}{\left(x-3\right)\left(x+2\right)}=\dfrac{1}{x-3}\)
d) \(\dfrac{2x}{x-2}-\dfrac{x}{x+4}=\dfrac{8x+8}{\left(x-2\right)\left(x+4\right)}\)
Giải các phương trình :
a) \(\dfrac{12}{x-1}-\dfrac{8}{x+1}=1\)
b) \(\dfrac{16}{x-3}+\dfrac{30}{1-x}=3\)
c) \(\dfrac{x^2-3x+5}{\left(x-3\right)\left(x+2\right)}=\dfrac{1}{x-3}\)
d) \(\dfrac{2x}{x-2}-\dfrac{x}{x+4}=\dfrac{8x+8}{\left(x-2\right)\left(x+4\right)}\)
e) \(\dfrac{x^3+7x^2+6x-30}{x^3-1}=\dfrac{x^2-x+16}{x^2+x+1}\)
f) \(\dfrac{x^2+9x-1}{x^4-1}=\dfrac{17}{x^3+x^2+x+1}\)
giải phương trình: \(\left(x+\dfrac{5-x}{\sqrt{x}+1}\right)^2=\dfrac{-1992\left(\sqrt{x}+1\right)}{5\sqrt{x}-x\sqrt{x}}\)
Giải các phương trình bằng cách đặt ẩn phụ:
a) \(3\left(x^2+x\right)^2-2\left(x^2+x\right)-1=0;\)
b) \(\left(x^2-4x+2\right)^2+x^2-4x-4=0;\)
c) \(x-\sqrt{x}=5\sqrt{x}+7;\)
d) \(\dfrac{x}{x+1}-10.\dfrac{x+1}{x}=3.\)
Giải các phương trình:
a) (x - 3)2 + (x + 4)2 = 23 - 3x; b) x3 + 2x2 - (x - 3)2 = (x - 1)(x2 - 2);
c) (x - 1)3 + 0,5x2 = x(x2 + 1,5); d) \(\dfrac{x\left(x-7\right)}{3}-1=\dfrac{x}{2}=\dfrac{x-4}{3};\)
e) \(\dfrac{14}{x^2-9}=1-\dfrac{1}{3-x};\) f) \(\dfrac{2x}{x+1}=\dfrac{x^2-x+8}{\left(x+1\right)\left(x-4\right)}.\)
giải pt sau:
15.\(\dfrac{7}{x-2}+\dfrac{8}{x-5}=3\)
16. \(\dfrac{x^2-3x+6}{x^2-9}=\dfrac{1}{x-3}\)
17.\(\dfrac{3}{x^2-4}=\dfrac{1}{x-2}+\dfrac{1}{x+2}\)
18.\(\dfrac{1}{2\left(x-1\right)}+\dfrac{8}{x^2-1}=\dfrac{1}{4}\)
Giải các phương trình sau bằng cách đặt ẩn phụ :
a) \(\left(4x-5\right)^2-6\left(4x-5\right)+8=0\)
b) \(\left(x^2+3x-1\right)^2+2\left(x^2+3x-1\right)-8=0\)
c) \(\left(2x^2+x-2\right)^2+10x^2+5x-16=0\)
d) \(\left(x^2-3x+4\right)\left(x^2-3x+2\right)=3\)
e) \(\dfrac{2x^2}{\left(x+1\right)^2}-\dfrac{5x}{x+1}+3=0\)
f) \(x-\sqrt{x-1}-3=0\)
Giải phương trình :
( x + \(\dfrac{1}{x}\))\(^2\) - 4,5( x + \(\dfrac{1}{x}\)) +5 = 0
