Question

数学题:先化简再求值(x分之X的平方+4-4)除的X平方+2x分之X的平方-4(其中X=-1)

Answer 1

(x分之X的平方+4-4)除的X平方+2x分之X的平方-4

=[(x²+4)/x-4] ÷ [(x²-4)/(x²+2x)]

=[(x²-4x+4)/x] ÷ [(x+2)(x-2)/x(x+2)]

=[(x-2)²/x] * [x(x+2)/(x-2)(x+2)]

=[(x-2)²x(x+2)] / [x(x-2)(x+2)]

=x-2

当x=-1时,原式=-1-2=-3