Question

Como calcular: x² + (x-3)² = (x+3)²

Answer 1

x²+ (x-3)² = (x+3)²
x² + x² -6x + 9 = x² +6x + 9
x² -12x = 0
x( x -12) = 0 

x' = 0
x''= x-12=0 =>  x=12  => x'' = 12