若a2+b2+2a﹣10b+26=0,求a+b﹣ab的值.
解:a2+b2+2a﹣10b+26=0,
a2+2a+1+b2﹣10b+25=0,
(a+1)2+(b﹣5)2=0,
则a+1=0,b﹣5=0,
解得,a=﹣1,b=5,
则a+b﹣ab=﹣1+5+5=9.