试说明:不论x,y取何值时,3a²-6a＋b²＋10b+28的值不小于0.

试说明:不论x,y取何值时,3a²-6a＋b²＋10b+28的值不小于0.
试说明:不论x,y取何值时,3a²-6a＋b²＋10b+28的值不小于0.

试说明:不论x,y取何值时,3a²-6a＋b²＋10b+28的值不小于0.
3a²-6a＋b²＋10b+28
=3（a²-2a+1)+(b²+10b+25)
=3(a-1)²+(b+5)²
≥0
∴不论x,y取何值时,3a²-6a＋b²＋10b+28的值不小于0