解方程: x-5/x-6+x-8/x-9=x-7/x-8+x-6/x-7 过程!
问题描述:
解方程: x-5/x-6+x-8/x-9=x-7/x-8+x-6/x-7 过程!
答
因为:x-5/x-6+x-8/x-9=x-7/x-8+x-6/x-7,所以:1+1/(x-6)+1+1/(x-9)=1+1/(x-8)+1+1/(x-7)
即:1/(x-6)+1/(x-9)=1/(x-8)+1/(x-7)
所以:1/(x-6)-1/(x-7)=1/(x-8)-1/(x-9)
所以:[(x-7)-(x-6)]/[(x-6)(x-7)]=[(x-9)-(x-8)]/[(x-8)(x-9)]
所以:(x-6)(x-7)=(x-8)(x-9)
即:x^2-13x+42=x^2-17x+72,则:4x=30,解得:x=15/2