How do i solve this system of ! x=y-8 -x-y=0

The first equation x=y-8 is, subtract y from each side, x-y=-8the second equation -x-y=0 is, multiply by -1,            x+y=0Now add and get                                                      2x+0=-8 or 2x=-8 or x=-4 Use this result in the second equation to get      -4+y=0 or y=4Or subtract the equations to get                                0-2y=-8 or y=4

7.666270253x10 raised to the 18th power

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