числитель(х-5)(х-7)+(х-1)(х-7)+(х-1)(х-3)=
=x^2+35-12x+x^2-8x+7+x^2+3-4x=3x^2-24x+45=3(x^2-8x+15)=3(x-3)(x-5)
знаминатель (х-1)(х-3)(х-5)(х-7)
=3/(x-1)(x-7)
1/(х-1)(х-3)+1/(х-3)(х-5)+1/(х-5)(х-7)=
приведем к общему знаменателю - (х-1)(х-3)(х-5)(х-7)
= [(x-5)*(x-7) + (x-1)*(x-7) + (x-1)*(x-3)]/(х-1)(х-3)(х-5)(х-7) =
= (x²-5x-7x+35 + x²-x-7x+7 + x²-x-3x+3)/(х-1)(х-3)(х-5)(х-7) =
= (3x²- 24x + 45)/(х-1)(х-3)(х-5)(х-7)=
= 3(x²- 8x + 15)/(х-1)(х-3)(х-5)(х-7)=
по теореме Виета
x²- 8x + 15 = 0
х1=3
х2=5
= 3(х-3)(х-5)/(х-1)(х-3)(х-5)(х-7)=
= 3/(х-1)(х-7)
числитель(х-5)(х-7)+(х-1)(х-7)+(х-1)(х-3)=
=x^2+35-12x+x^2-8x+7+x^2+3-4x=3x^2-24x+45=3(x^2-8x+15)=3(x-3)(x-5)
знаминатель (х-1)(х-3)(х-5)(х-7)
=3/(x-1)(x-7)
1/(х-1)(х-3)+1/(х-3)(х-5)+1/(х-5)(х-7)=
приведем к общему знаменателю - (х-1)(х-3)(х-5)(х-7)
= [(x-5)*(x-7) + (x-1)*(x-7) + (x-1)*(x-3)]/(х-1)(х-3)(х-5)(х-7) =
= (x²-5x-7x+35 + x²-x-7x+7 + x²-x-3x+3)/(х-1)(х-3)(х-5)(х-7) =
= (3x²- 24x + 45)/(х-1)(х-3)(х-5)(х-7)=
= 3(x²- 8x + 15)/(х-1)(х-3)(х-5)(х-7)=
по теореме Виета
x²- 8x + 15 = 0
х1=3
х2=5
= 3(х-3)(х-5)/(х-1)(х-3)(х-5)(х-7)=
= 3/(х-1)(х-7)