|a-3|+(b+1)平方=0
|a-3|=0
(b+1)平方=0
a-3=0
a=3
b+1=0
b=-1
2a(-a-3b)-3b(2a+b)
=2*3[-3-3*(-1)]-3(-1)[2*3+(-1)]
=6*0+3*5
=15