если f(x)=4/x, то f(x+1)=4/(x+1);
g(x)=1/x, => g(x^2-1)=1/(x^2-1);
4/(x+1)-1/(x^2-1)=4;
(4x-5)/(x^2-1)=4;
4x-5=4x^2-4;
4x^2-4x+1=0
(2x-1)^2=0
2x=1
x=1/2
если f(x)=4/x, то f(x+1)=4/(x+1);
g(x)=1/x, => g(x^2-1)=1/(x^2-1);
4/(x+1)-1/(x^2-1)=4;
(4x-5)/(x^2-1)=4;
4x-5=4x^2-4;
4x^2-4x+1=0
(2x-1)^2=0
2x=1
x=1/2