Use 3-digit arithmetic with no pivoting?

Question

Use 3-digit arithmetic with no pivoting to solve the following system:

 

10^-3x-y=1,

x+y=0.

 

The book says the answer is (0, -1). Please show all your work step by step. Thanks.

Answer 1

x+y=0 -> x=-y (subtract by y each side)

use substitution property

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Sorry, as I was doing this, I realized the problem you have provided is wrong given the provided info. (0,-1) means x=0 and y=-1. x+y therefore is -1, not 0, which does not fit your given statement.

also, the answer to this would be kind of crazy.

x would be 1.001001001 repeating, and y would be that but negative instead of positive. A very unusual answer to find.