Question

Tìm x biết:

d) 6.(x+1)²-2.(x+1)³+2.(x-1).(x²+x+1)=1

e) (x-2)²-(x-2).(x+2)=0

f) x²-4x+4=25

Giải chi tiết giúp mình nha.Cảm ơn nhiều.

Answer 1

\(6,\Rightarrow6x^2+12x+6-2x^3-6x^2-6x-2+2x^3-2=1\\ \Rightarrow6x=-1\Rightarrow x=-\dfrac{1}{6}\\ 7,\Rightarrow\left(x-2\right)\left(x-2-x-2\right)=0\\ \Rightarrow-4\left(x-2\right)=0\\ \Rightarrow x-2=0\Rightarrow x=2\\ 8,\Rightarrow\left(x-2\right)^2-25=0\\ \Rightarrow\left(x-2-5\right)\left(x-2+5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=7\\x=-3\end{matrix}\right.\)