b, Rút gọn biểu thức A= [2(x-2 cănx +1)/ x-4 - 2căn x -1 / cănx +2 ]: căn x / căn x -2 với ( x>0, x khác 4)
Giải thích
b)2x−2x+1x−4−2x−1x+2:xx−2x>0,x≠4=2x−2x+1x−2x+2−2x−1x−2x+2x−2:xx−2=2x−4x+2−2x+x+4x−2x+2x−2.x−2x=xx+2x−2.x−2x=1x+2
Vậy A=1x+2
b)2x−2x+1x−4−2x−1x+2:xx−2x>0,x≠4=2x−2x+1x−2x+2−2x−1x−2x+2x−2:xx−2=2x−4x+2−2x+x+4x−2x+2x−2.x−2x=xx+2x−2.x−2x=1x+2
Vậy A=1x+2