已知a+b=6 ab=7则a^2-3ab+b^2=_____

问题描述:

已知a+b=6 ab=7则a^2-3ab+b^2=_____

a^2-3ab+b^2
=a²+2ab+b²-5ab
=(a+b)²-5ab
=6²-35
=36-35
=1