Respuesta :

Answer:

[tex](x-3)^2 =21[/tex]

Step-by-step explanation:

[tex]~~~~~~~x^2-6x-12=0\\\\\implies x^2 -6x +9-21=0 \\\\\implies x^2 -2\cdot x \cdot 3 +3^2=21\\\\\implies (x-3)^2 =21[/tex]