Respuesta :

- 9 x * ( x - 1 ) + ( - x ) * ( - 3 x + 4 ) =
= - 9 x² + 9 x - x * ( - 3 x + 4 ) =
= - 9 x² + 9 x + 3 x² - 4 x =
= - 9 x² + 3 x² + 9 x - 4 x =
= - 6 x²  + 5 x