(ln(x-7)/(x+1))'=(ln(x-7)'(x+1))-(x+1)'ln(x-7))/(ln(x-7)/(x+1)*(x+1)= =(x+1)/(x-7)-ln(x-7)/(x+1)*(x+1)=((x+1)-(x-7)ln(x-7))/(x+1)*(x+1)