We need to form the matrices:

`A=((1,1,1),(2,-5,0),(0,5,-1))`, `\ X=((I_A),(I_B),(I_C))\ ` and `\ C=((0),(6),(-3))`

Using Scientific Notebook (or any Computer Algebra System), we find:

`A^-1 = ((0.294,0.353,0.294),(0.118,-0.059,0.118),(0.588,-0.294,-0.412))`

and so (continuing to use Scientific Notebook, with rounding to 3 decimal places):

`((I_A),(I_B),(I_C))=A^-1C`

`=((0.294,0.353,0.294),(0.118,-0.059,0.118),(0.588,-0.294,-0.412))((0),(6),(-3))`

`=((1.236),(-0.708),(-0.528))`

Therefore

`I_A= 1.236\ "A"`,

`I_B= -0.708\ "A"` and

`I_C= -0.528\ "A"`