(X-4/X-5)-(X-5/X-6)=(X-7/X-8)-(X-8/X-9)咋做拜托各位了 3Q

(X-4/X-5)-(X-5/X-6)=(X-7/X-8)-(X-8/X-9) [(X-4)(X-6)-(X-5)^2]/[(X-5)(X-6)]=[(X-7)(X-9)-(X-8)^2/[(X-8)(X-9)] 1/(X-5)(X-6)=1/(X-8)(X-9) X^2-11X+30=X^2-17X+72 6X=42 X=7