If you mean two of the same numbers that add to make 75, it's 37.5 ....?
In the matrix, the first row is exactly twice the second. This implies that the determinant is zero.
If the matrix system has determinant zero, the system has either no solutions or infinite solutions.
However, just like in the matrix, in the constant vector the first term is twice the second. This means that the system has infinite solutions.
In fact, if you write this system in expanded form, you can see that it generates two equations, the first being twice the second:

I don't think you can solve for x unless they give you what that equation equals (for example 5x+8=7)
I'm pretty sure that is as simplified as it can be