3(3x - 2) = (x + 4)(4 - x)Ayudaaaaa?

3(3x - 2) = (x + 4)(4 - x)

9x - 6 = 4x - x² + 16 - 4x

9x - 6 = 16 - x²

x² + 9x = 16 + 6

x² + 9x - 22 = 0

x = { - 9 + - √(9² - (4 * 1 * - 22))} / 2.

1

x = { - 9 + - √(81 + 88)} / 2

x = { - 9 + - √169} / 2

x = { - 9 + - 13} / 2

x₁ = { - 9 - 13} / 2 = - 22 / 2 = - 11

x₂ = { - 9 + 13} / 2 = 4 / 2 = 2

Comprobación :

3((3 * 2) - 2) = (2 + 4)(4 - 2)

18 - 6 = 6 * 2

12 = 12

3((3 * - 11) - 2) = ( - 11 + 4)(4 - ( - 11)) - 99 - 6 = - 7 * 15 - 105 = - 105

Respuesta :

x₁ = - 11

x₂ = 2.