Question

x²=12x
x²=-5x
13x²=169

Answer 1

   x² = 12x
   x² - 12x = 0
   x(x - 12)=0
   
   x' = 0
   x"--> x-12 = 0 --> x = 12
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   x² = - 5x
  x² + 5x = 0
  x(x + 5) = 0
 
 x' = 0
x" --> x+5=0 --> x = - 5
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  13x² = 169
  13x² = 13²
     x² = 13²/13
     x² = 13 ---> x = ±√13