a: \(\Leftrightarrow\left\{{}\begin{matrix}x-2>=0\\x^2-3x+2=x^2-4x+4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>=2\\x=2\end{matrix}\right.\Leftrightarrow x=2\)
b: \(\text{Δ}=\left(-9\right)^2-4\cdot1\cdot2=81-8=73>0\)
Phươg trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{9-\sqrt{73}}{2}\\x_2=\dfrac{9+\sqrt{73}}{2}\end{matrix}\right.\)