1/(x-7)-1/(x-5)=1/(x-6)-1/(x-4)(x-7-x+5)/(x-7)(x-5)=(x-6-x+4)/(x-6)(x-4)-2/(x²-12x+35)=-2/(x²-10x+24)∴x²-12x+35=x²-10x+24-12x+10x=24-35-2x=-11x=5.5