Question

计算9998^3-2×9998^2-9996/9998^3+9998^2-9999

Answer 1

大数设为字母更好做.

设X=9998,

原式=(X^3-2X^2-X+2)/(X^3+X^2-X-1)

=［X^2(X-2)-(X-2)］/［X^2(X+1)-(X-1)］

=(X-2)(X^2-1)/［(X+1)(X^2-1)］

=(X-2)/(X+1)

=9996/9999

=3332/3333.