1
18/x+18/(x+27)=1
x≠0,x≠-27
18*(x+27)+18*x=x(x+27)
x²+27x-18(x+27+x)=0
x²+27x-36x-486=0
x²-9x-486=0
x1+x2=9 Y x1*x2=-486
x1=-18 U x2=27
2
1/x+1/(x+6)=1/4
x≠0,x≠-6
4(x+6)+4x=x(x+6)
x²+6x-4(x+6+x)=0
x²+6x-8x-24=0
x²-2x-24=0
x1+x2=2 U x1*x2=-24
x1=6
x2=-4