y=(x^2+7x+22)/(x+1)=[(x^2+x)+(6x+6)+16]/(x+1)=[x(x+1)+6(x+1)+16]/(x+1)=x+6+16/(x+1)=(x+1)+16/(x+1)+5x=2√[(x+1)*16/(x+1)]（利用基本不等式定理）=2√[(x+1)*16/(x+1)]=2*4=8(x+1)+16/(x+1)