Question

a) x\(^3\) -3x\(^2\) +3x-1

b) \(\frac{1}{x-2}\)+3 = \(\frac{x-3}{2-x}\)

c) 1+ \(\frac{1}{x+2}\) = \(\frac{12}{8+x^3}\)

d) \(\frac{3a-1}{3a+1}\) + \(\frac{a-3}{a+3}\)

Answer 1

Lời giải:

a) x^3-3x^2+3x-1=0$

$\Leftrightarrow (x-1)^3=0\Rightarrow x=1$

b) ĐKXĐ: $x\neq 2$

\(\frac{1}{x-2}+3=\frac{x-3}{2-x}\)

\(\Leftrightarrow \frac{3x-6}{x-2}=\frac{3-x}{x-2}\)

\(\Rightarrow 3x-6=3-x\Rightarrow x=2,25\)

c) ĐKXĐ: $x\neq -2$

\(1+\frac{1}{x+2}=\frac{12}{8+x^3}\)

\(\Leftrightarrow \frac{x+3}{x+2}=\frac{12}{(x+2)(x^2-2x+4)}\)

\(\Rightarrow (x+3)(x^2-2x+4)=12\)

$\Leftrightarrow x^3+x^2-2x=0$

$\Leftrightarrow x(x+2)(x-1)=0$

$\Rightarrow x=0$ hoặc $x=1$ (do $x\neq -2$)

Vậy........

d) Đề bài không rõ.