d/
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)-\left(x+2\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
e/
\(\Leftrightarrow x^2-x-3x+3=0\)
\(\Leftrightarrow x\left(x-1\right)-3\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
f/
\(\Leftrightarrow3x\left(x-4\right)+12\left(x-4\right)=0\)
\(\Leftrightarrow3\left(x+4\right)\left(x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-4\end{matrix}\right.\)
g/
\(\Leftrightarrow\left(2x-1\right)\left(5-3x\right)-\left(x+2\right)\left(5-3x\right)=0\)
\(\Leftrightarrow\left(5-3x\right)\left(2x-1-x-2\right)=0\)
\(\Leftrightarrow\left(5-3x\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\frac{5}{3}\end{matrix}\right.\)
a/
Đặt \(x-1=t\)
\(\Rightarrow\left(t+3\right)^4+\left(t-3\right)^4=162\)
\(\Leftrightarrow2t^4+108t^2=0\)
\(\Leftrightarrow2t^2\left(t^2+54\right)=0\)
\(\Leftrightarrow t=0\Rightarrow x=1\)
b/
Bạn coi lại đề, bài này ít nhất phải lớp 9 vì nghiệm xấu
c/
\(\Leftrightarrow x^2-\left(x^2+2x+1\right)=0\)
\(\Leftrightarrow-2x-1=0\)
\(\Leftrightarrow x=-\frac{1}{2}\)
