Question

Giải các Phtr sau ☘Tiểu Tuyết☘

a) 26x³ - 12x² + 13x = 6

b) (x + 1)³ - ( x - 1)³ = 6 ( x² + x + 1)

c) \(\frac{3x-1}{x-1}-\frac{2x+5}{x+3}-\frac{8}{x^2+2x-3}=1\)

Answer 1

a)\(26x^3-12x^2+13x=6\)

\(\Rightarrow26x^3-12x^2+13x-6=0\)

\(\Rightarrow2x^2\left(13x-6\right)+\left(13x-6\right)=0\)

\(\Rightarrow\left(13x-6\right)\left(2x^2+1\right)=0\)

\(\Rightarrow\left[\begin{matrix}13x-6=0\\2x^2+1=0\end{matrix}\right.\)\(\Rightarrow\left[\begin{matrix}x=\frac{6}{13}\\2x^2+1>0\left(loai\right)\end{matrix}\right.\)

Answer 2