初二数学题化简求职
19.(x/x-1)-(x+3/x2-1)*(x2+2x+1/x+3) x=根号2+1
21.[(2x-3/x)-1]/[x2-9/x]x=2
20.[(2/a-1)-1/(a+1)]*(a2-1)a=根号3 -3
22.a+1/a-1 - a/a2-2a+1a=1-根号2