当x等于多少时,分式x2-1/x+1的值为零.化简12/m2-9+2/m+3的结果是?

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当x等于多少时,分式x2-1/x+1的值为零.化简12/m2-9+2/m+3的结果是?

当x等于多少时,分式x2-1/x+1的值为零.化简12/m2-9+2/m+3的结果是?
当x等于多少时,分式x2-1/x+1的值为零.化简12/m2-9+2/m+3的结果是?

当x等于多少时,分式x2-1/x+1的值为零.化简12/m2-9+2/m+3的结果是?

(1)x^2-1=0且x+1不等于0,所以:x=1
(2)12/(m^2-9)+2/(m+3)==[12+2(m-3)]/[(m+3)(m-3)]=(2m+6)/[(m+3)(m-3)]=2/(m-3)

1、因为x2-1=(x+1)(x-1)=0,且x+1≠0 所以,x-1=0 x=1
2、12/(m2-9)+2/m+3
=12/(m+3)(m-3)+2/(m+3)
=(12+2m-6)/(m+3)(m-3)
=2(m+3)/(m+3)(m-3)
=2/(m-3)

做法一:1、因为x2-1=(x+1)(x-1)=0,且x+1≠0 所以,x-1=0 x=1
2、12/(m2-9)+2/m+3
=12/(m+3)(m-3)+2/(m+3)
=(12+2m-6)/(m+3)(m-3)
=2(m+3)/(m+3)(m-3)
=2/(m-3)
做法二:(1)x^2-1=0且x+1不等于0,所以:x=1
(2)12/(m^2-9)+2/(m+3)==[12+2(m-3)]/[(m+3)(m-3)]=(2m+6)/[(m+3)(m-3)]=2/(m-3)