∵﹙a+b﹚²=1,﹙a－b﹚²=25
∴a²+b²=[(a+b)²+(a-b)²]／2=13
ab=[(a+b)²-(a-b)²]／4=-6
a²＋ab+b²
=a²+b²-ab
=13-(-6)
=19