Question

先化简,再求值:[(a的平方+2a分之a-2)-(a的平方+4a+4分之a-1)除以(a+2分之a-4),其中a满足a的

Answer 1

[(a-2)/a(a+2)-(a-1)/(a+2)^2]除以((a-4)/(a+2)

=(a^2-4-a^2+a)/a(a+2)^2 * (a+2)/(a-4)

=(a-4)/a(a+2)^2 * (a+2)/(a-4)

=1/a(a+2)

(a-1)^2=0

a=1

代入

=1/2