Respuesta :

Use FOIL and simply, First times First, Outside times Outside, Inside times Inside, Last times Last.

(3x+5)(4x-1)
3x * 4x = 12x²
3x * -1 = -3x
5 * 4x = 20x
5 * -1 = -5

12x² - 3x + 20x - 5

Now simplify by adding -3x to 20x and get:

12x² + 17x - 5