已知a+b=4，ab=2，

(a+b)^2=16
a^2+b^2+2ab=16
a^2+b^2=16-2*2=12
3a^2+2ab+3b^2
=3(a^2+b^2)+2ab
=3*12+2*2
=36+4
=40

3a²+2ab+3b²
=3(a+b)²-4ab
=3*4²-4*2
=40

b=4-a a(4-a)=2
a^2-4a+2=0
a1=2+根号2 a2=2-根号2
b1=2-根号2 b2=2+根号2
带入得：
3a^2+2ab+3b^2=40

3a²+2ab+3b²
=3（a+b）^2-4ab
=3*4^2-4*2
=48-8
=40

解：2ab=2*2=4
(a+b)^2=a^2+2ab+b^2=4*4=16
16-4=14=a^2+b^2
14*3+4=46=3a²+2ab+3b²

3a²+3b²=3(a+b)²=48 2ab=2(ab)=4 所以答案是52