如果x=300，则xx−3-x+6x2−3x+1x的值为（）A.0B.101990C.111110D.101100

Question

(x)/(x−3)-(x+6)/(x2−3x)+(1)/(x)的值为（　　）
A. 0
B. (101)/(990)
C. (111)/(110)
D. (101)/(100)(x)/(x−3)xxx−3x−3(x+6)/(x2−3x)+(1)/(x)的值为（　　）
A. 0
B. (101)/(990)
C. (111)/(110)
D. (101)/(100)(x+6)/(x2−3x)x+6x+6x2−3xx2−3xx2−3xx2−3x2−3x(1)/(x)的值为（　　）
A. 0
B. (101)/(990)
C. (111)/(110)
D. (101)/(100)(1)/(x)11xx

(101)/(990)
C. (111)/(110)
D. (101)/(100)(101)/(990)101101990990
(111)/(110)
D. (101)/(100)(111)/(110)111111110110
(101)/(100)(101)/(100)101101100100

Answer 1

原式=(x)/(x−3)-(x+6)/(x(x−3))+(1)/(x)
=(x2)/(x(x−3))-(x+6)/(x(x−3))+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x)/(x−3)xxxx−3x−3x−3-(x+6)/(x(x−3))+(1)/(x)
=(x2)/(x(x−3))-(x+6)/(x(x−3))+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x+6)/(x(x−3))x+6x+6x+6x(x−3)x(x−3)x(x−3)+(1)/(x)
=(x2)/(x(x−3))-(x+6)/(x(x−3))+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (1)/(x)111xxx
=(x2)/(x(x−3))-(x+6)/(x(x−3))+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x2)/(x(x−3))x2x2x22x(x−3)x(x−3)x(x−3)-(x+6)/(x(x−3))+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x+6)/(x(x−3))x+6x+6x+6x(x−3)x(x−3)x(x−3)+(x−3)/(x(x−3))
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x−3)/(x(x−3))x−3x−3x−3x(x−3)x(x−3)x(x−3)
=(x2−x−6+x−3)/(x(x−3))
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x2−x−6+x−3)/(x(x−3))x2−x−6+x−3x2−x−6+x−3x2−x−6+x−32−x−6+x−3x(x−3)x(x−3)x(x−3)
=(x2−9)/(x(x−3))
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x2−9)/(x(x−3))x2−9x2−9x2−92−9x(x−3)x(x−3)x(x−3)
=((x−3)(x+3))/(x(x−3))
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． ((x−3)(x+3))/(x(x−3))(x−3)(x+3)(x−3)(x+3)(x−3)(x+3)x(x−3)x(x−3)x(x−3)
=(x+3)/(x)，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (x+3)/(x)x+3x+3x+3xxx，
当x=300时，原式=(303)/(300)=(101)/(100)，
故选D． (303)/(300)303303303300300300=(101)/(100)，
故选D． (101)/(100)101101101100100100，
故选D．