.
y= x^2 - 6x + 5
y= x - 1
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Substitute y from the second equation into the first one. You will get
=
, or
=
.
The roots are x = 6 and x = 1.
It means that the pairs (x,y) = (6,5) and (x,y) = (1,0) are the solutions of your original system.