Respuesta :

Answer:

[tex]{ \tt{7 {x}^{3} = 28x }} \\ \\ { \tt{7 {x}^{2} = 28}} \\ \\ { \tt{ {x}^{2} = 4}} \\ \\ { \tt{x = \sqrt{ 4 } }} \\ \\ { \boxed{ \tt{x = {}^{ + }2 } } \: \: and \: { \boxed{ \tt{x = {}^{ - } 2}}}}[/tex]