How do I use the nonsymmetric_general function from Accelerate?

So I've read the documentation, downloaded the Accelerate source, and created a simple example.

I'm attempting to solve a system of two equations, 90x+85y=400, and y-x=0.

The result should be just greater than 2.25 for both x and y. What I get is [x,y]=[2.2857144, 205.7143].

I'm new to this, so I'm sure I've misread the docs, but I can't see where.

Here is the code I modified to do my experiment.

do{

    let aValues: [Float] = [85, 90,

                        1,-1]

    /// The _b_ in _Ax = b_.

    let bValues: [Float] = [400,0]

    /// Call `nonsymmetric_general` to compute the _x_ in _Ax = b_.

    let x = nonsymmetric_general(a: aValues,

                                 dimension: 2,

                                 b: bValues,

                                 rightHandSideCount: 1)

    /// Calculate _b_ using the computed _x_.

    if let x = x {

        let b = matrixVectorMultiply(matrix: aValues,

                                     dimension: (m: 2, n: 2),

                                     vector: x)

        /// Prints _b_ in _Ax = b_ using the computed _x_: `~[70, 160, 250]`.

        print("\nx = ",x)

        print("\nb =", b)

    }

}

What did I misunderstand?

Thanks