if you write the augmented matrices for these problems, you will end up with matrix equations of the form:

to solve for using the inverse matrix method, we simply multiply both sides by the matrix to obtain

For example, you first system of equations can be represented by:

............ .................. ...............

........... .................. ...............

I hope you see how we got this. now, find the inverse of and multiply the right side by it (on the left)