1)x²+2x/x+4 = 8/x+4;x²+2x-8=0;x=-2±√2²-4×1(-8)/2×1;x=-2±√4+32/2;x=-2±√36/2;x=-2+6/2;x=-2-6/2;x=2
2)x+3/x-2x+10/x-3=0;(x-3)(x+3)-x(2x+10)/x(x-3)=0;x²-9-2x²-10x/x(x-3)=0;-x²-9-10x/x(x-3)=0;x²+10x+9=0;x=-10±√100-36/2;x=-10±√64/2;x=-10-8/2;x=-1;x=-9
3)x²-8x/5-x=15/x-5;(x²-8x)(x-5)-15(5-x)=0;x³-5x²-8x²+40x-75+15x=0;x³-13x²+55x-75=0;x³-3x²-10x²+30x+25x-75=0;x²(x-3)-10x(x-3)+25(x-3)=0;(x-3)(x²-10x+25)=0;(x-3)(x-5)²=0;x-3=0;(x-5)²=0;x=3;x=5;