1:a²+b²-4a+6b+13=0
(a-2)^2+(b+3)^2=0 a=2,b=-3
a的b次方=( -1/8 )
2:.(1-a²)(1-b²)-4ab
=1-b²-a²+a²b²-4ab
=1+a²b²-(a²+b²+2ab)-2ab
=1+a²b²-2ab-(a+b)^2
= (ab-1)^2-(a+b)^2
=(ab-1+a+b)(ab-1-a-b)