f(x)=x²-3x+2

f(x)=x²-3x+2
f(x)=x²-3x+2

f(x)=x²-3x+2
f(x)=x²-3x+2
f(x)=(x²-3x+9/4)-1/4
f(x)=(x-3/2)²-1/4
∴函数开口向上,有最小值,最小值为：f(3/2)=-1/4
1/4表示4分之1

f(x)=x²-3x+2
=(x-1)(x-2)