I am trying to solve some very basic ODE systems:

```py
t = symbols("t")
x, y = symbols("x y", cls=Function)
a = dsolve_system([
  Eq(y(t).diff(t), 1),
  Eq(x(t).diff(t), 1),
])

```

Output:

```py
[[Eq(x(t), C1 + Integral(1, t)), Eq(y(t), C2 + Integral(1, t))]]

```

I am expecting something like `x(t) = C1 + t` and `y(t) = C2 + t`, but for some reason, the integrals are not getting solved.

When I tried to provide initial conditions:

```py
t = symbols("t")
x, y = symbols("x y", cls=Function)
a = dsolve_system([
  Eq(y(t).diff(t), 1),
  Eq(x(t).diff(t), 1),
], ics={x(0): 1, y(0): 2})

```

The program just errored out:

```
NotAlgebraic                              Traceback (most recent call last)
<ipython-input-38-86edc5171650> in <module>()
      4   Eq(y(t).diff(t), 1),
      5   Eq(x(t).diff(t), 1),
----> 6 ], ics={x(0): 1, y(0): 2})
      7 a

14 frames
/usr/local/lib/python3.7/dist-packages/sympy/polys/numberfields.py in _minpoly_compose(ex, x, dom)
    583         res = _minpoly_rootof(ex, x)
    584     else:
--> 585         raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
    586     return res
    587 

NotAlgebraic: Integral(1, (t, 0)) doesn't seem to be an algebraic element

```