Y1=-0.5-X.^3*0.5

Y1 =

  Columns 1 through 7

    3.5000    1.1875         0   -0.4375   -0.5000   -0.5625   -1.0000

  Columns 8 through 9

   -2.1875   -4.5000

>> Y2=2/3-X.^2*2/3;
>> plot(X,Y1,X,Y2);
>> grid
>> % solve
>> syms x y
>> [x,y]=solve('x^3-2*y=1','x^2+3*y=2');
>> vpa(x,4)

ans =

             1.137
 - 0.902 - 1.113*i
 - 0.902 + 1.113*i

>> vpa(y,4)

ans =

            0.2355
 0.8082 - 0.6691*i
 0.8082 + 0.6691*i

>>