Question

当1/x=14-x时,求{[(x^2-5)/(x-1)+1]*[(x^3-1)/(x^2-2x)]}/(x+3)的值

Answer 1

1/x=14-x

x+1/x=14

原式=[(x²-5+x-1)/(x-1)][(x-1)(x²+x+1)/x(x-2)]/(x+3)

=[(x+3)(x-2)/(x-1)][(x-1)(x²+x+1)/x(x-2)]/(x+3)

=(x²+x+1)/x

=x+1+1/x

=14+1

=15