Respuesta :

4x^2-5x+15 is the answer.

Annder

Step-by-step explanation:

= 3(x-7) + 4(x² - 2x + 9)

= 3x - 21 + 4x² - 8x + 36

= 4x² + 3x - 8x + 36 - 21

= 4x² - 5x + 15