Question

已知x的平方+x-1=0,求x(1-1-x分之2)除以(x+1)-x平方-2x+1分之x(x的平方

-1)

Answer 1

　x[1-2/(1-x)]/(x+1)-x(x-1)/(x-2x+1)
=(x+1)/[(x-1)(x+1)]-x(x+1)/(x-1)
=1/(x-1)-x(x+1)/(x-1)
=-(x+x-1)/(x-1)
=0