若a=3-b则2a²＋4ab＋2b²-6的值是?

若a=3-b则2a²＋4ab＋2b²-6的值是?
若a=3-b则2a²＋4ab＋2b²-6的值是?

若a=3-b则2a²＋4ab＋2b²-6的值是?
a=3-b,得a+b=3
2a²+4ab+2b²-6
=2(a²+2ab+b²)-6
=2(a+b)²-6
=2*3²-6
=18-6
=12