Relax

Respuesta :

Step-by-step explanation:

(3x-1)(x+1)=3(3x-4+x²)

open the brackets

=3x²+3x-x-1=9x-12+3x²

=3x²+2x-1=9x-12+3x²

collecting like terms

=3x²-3x²+2x-9x=-12+1

=-7x=-11

=x=11/7