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问题: 这个问题么做

X+1/X+4 + X+2/X+5=X+3/X+6 + X+4/X+7 .求X的值

解答:

(x+1)/(x+4)+(x+2)/(x+5)-(x+3)/(x+6)-(x+4)/(x+7)=0
(x*x+8*x+7-x*x-8*x-16)/[(x+4)*(x+7)]+(x*x+8*x+12-x*x-8*x-15)/[(x+5)*(x+6)]=0
9/(x*x+11*x+28)+3/(x*x+11*x+30)=0
3*x*x+33*x+90+x*x+11*x+28=0
2*x*x+22*x+59=0
x=(-11±根号(3))/2