How to use an array in dsolve function?

I have an ODE system of two equations, but want to minimize it with using just one equation with the result of the other.

1)

t=linspace(0,2,3);
syms x(t) y(t);
inits='x(0)=2,y(0)=0';
[x,y]=dsolve('Dx=y','Dy=(y*2)-x', inits);

x = 2*exp(t) - 2*t*exp(t);
y = -2*t*exp(t);

xx=eval(vectorize(x));
xx = 2.0000; 0; -14.7781

yy=eval(vectorize(y));
yy = 0; -5.4366; -29.5562

After I had got the results, I tried to solve it just with one equation and use xx array in Dy equation.

2)

inits='y(0)=0';
[y]=dsolve('Dy=(y*2)-xx', inits);

y = xx/2 - (xx*exp(2*t))/2
yy=eval(vectorize(y));

yy = 0; 0; 396.0397

The value of yy are not the same as it was in the first example. How to get the same result using array?