\underset{x\to 0}{\mathop{\lim }}\,\left( {{x}^{2}}-3x+2 \right)=\underset{x\to 0}{\mathop{\lim }}\,{{x}^{2}}-\underset{x\to 0}{\mathop{\lim }}\,3x+\underset{x\to 0}{\mathop{\lim }}\,2={{0}^{2}}-3\cdot 0+2=2