3a²-2a²b²+3b²
=3(a²+b²+2ab)-6ab-2(ab)²
=3(a+b)²-6x(-2)-2x(-2)²
=3x3²+12-8
=9+4
=13
手机提问的朋友在客户端右上角评价点【满意】即可.