a平方-4/a+2+a+2
=(a-2)(a+2)/(a+2)+a+2
=a-2+a+2
=2a
(2a-b)平方-b平方,其中a=-2,b=3
=4a²-4ab+b²-b²
=4a²-4ab
=4*(-2)²-4*(-2)*3
=16+24
=40
2/x-1=1/x-2
2(x-2)=x-1
2x-4=x-1
2x-x=-1+4
x=3
a平方-4/a+2+a+2
=(a-2)(a+2)/(a+2)+a+2
=a-2+a+2
=2a
(2a-b)平方-b平方,其中a=-2,b=3
=4a²-4ab+b²-b²
=4a²-4ab
=4*(-2)²-4*(-2)*3
=16+24
=40
2/x-1=1/x-2
2(x-2)=x-1
2x-4=x-1
2x-x=-1+4
x=3