1) x+5/x-5=x-5/x+5
(x+5)^2-(x-5)^2 / (x-5)(x+5)=0
x^2+10x+25-x^2+10x-25=0
20x=0
2) 4x+1/3=3X-1/x
4x^2+x-9x+3/3x=0
4x^2-8x+3=0
x1=0,5 ; x2=1,5
3) x-4/2=10+2x/x
x^2-4x-20-4x/2x=0
x^2-8x-20=0
x1=10 ; x2=-2
4) 4x+1/x-3=3x-8/x+1=0
4x^2+5x+1-3x^2+17-24=0
x1=-23 ; x2=1