The answer is: x² – 6x + 9 = 0 .
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Step-by-step explanation:
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Given: (x – 3)² = 0 ; write as: general form: "ax² + bx + c = 0"; a ≠ 0 .
Note: (x – 3)² = (x – 3)(x – 3) = x² – 3x – 3x + 9 = x² – 6x + 9 ;
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Rewrite: (x – 3)² = 0 ; → 
 as: x² – 6x + 9 = 0 ; which is our answer.
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→ x² – 6x + 9 = 0 ; is in "general form", or "standard equation format"; that is: " ax² + bx + c = 0 "; (a ≠ 0) ;
 → in which: 
 a = 1 (implied coefficient, since anything multiplied by "1" is that same value);
 b = -6; 
 c = 9
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