Creating a Matrix from the output of equations

I'm looking to evaluate several equations and put the output of these equations into a matrix to eventually solve this matrix.

The matrix I'm looking to output is as follows:

| -2 1+B 0 | * | theta 1 | = | 0 |

| 1-B -2 1+B | | theta 2 | | 0 |

| 0 1-B -2 | | theta 3 | | 0 |

With B being .35*n

n is first evaluated at 2, then will be evaluatued at 1, then 0

The size of the matrix (mxm) will be determined 10/n. So the first matrix will be a 5x5, then with n=1 the matrix should be 10x10.