Question 1096954
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Also (as an addition to the @MathTutor's solution) if the base 

x^2 - 7x + 7 = 1,


then any degree of the base is 1.


x^2 - 7x + 7 = 1  ====>  x^2 -7x + 6 = 0  ====>  (x-6)*(x-1) = 0  ====>  the roots are x= 6  and  x= 1.
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So, add these values x= 6 and x= 1 to the list of solutions.