S1=(x+1)×(x+2)=x^2+3x+2
S2=(x+6)(x-2)=x^2+4x-12
S1-S2=(x^2+3x+2)-(x^2+4x-12)
=14-x
当14-x>0即6<x<14时,s1>s2
当14-x=0即x=14时,s1=s2
当14-x<0即x>14时,s1<s2
S1=(x+1)×(x+2)=x^2+3x+2
S2=(x+6)(x-2)=x^2+4x-12
S1-S2=(x^2+3x+2)-(x^2+4x-12)
=14-x
当14-x>0即6<x<14时,s1>s2
当14-x=0即x=14时,s1=s2
当14-x<0即x>14时,s1<s2