Помогите с решением (алгебра)

Ответ. 1.(2*x^4+2*x^3-5*x^2-2)/(x^3+x-2)=2*x-(25*x+14)/(4*(x^2+x+2))-3/(4*(x-1))+2;
2. 3*x^4+3*x^3-8*x^2-2*x+4=(x-1)*(x+2)*(3*x^2-2)=0; x1=1; x2=-2; x3=(2/3)^0,5; x4=-(2/3)^0,5;

3. (x^2)/(x+3)+x/(x-2)-(11*x-12)/((x+3)*(x-2))=(x^3-2*x^2+x^2+3*x-11*x+12)/((x+3)*(x-2))=((x+3)*(x-2)^2)/((x+3)*(x-2))=0; x-2=0; x=2;

4. x^2-y^2=19; x-y=7; y=x-7; x^2-(x-7)^2=19;2*(7*x-34)=0; x=34/7; y=-12/7;