To solve this system of equations, we can substitute the second equation into the first equation. This will give us:

х3 + 7 + у3 = 13

Subtracting 7 from both sides, we get:

х3 + у3 = 6

Now we have a new equation:

х3 + у3 = 6

This equation is equivalent to the first equation, so we can substitute it back into the first equation to get:

6 = 13

Since this is a contradiction, there is no solution to this system of equations.