Question

当X取和值时,分式[X+3]除以{(X-2)(X+1)}有意义

Answer 1

答：k≠3

6/(x-1)=(x+k)/[x*(x-1)]-3/x

6x/[x*(x-1)]=(-2x^2+kx+3x)/[x*(x-1)]

6x=-2x^2+kx+3x

2x^2-kx+3x=0

x*(2x+3-k)=0

k≠3