a²+b²-8a+12b+52=0
(a²-8a+16)+(b²+12b+36)=0
(a-4)²+(b+6)²=0
两个平方数的和为0,这两个数都是0
a-4=0
b+6=0
a=4,b=-6
3a+2b=12-12=0