Question

se considera expresia E(x) =​

Answer 1

Răspuns:

Explicație pas cu pas:

(x - 1)(x + 2) = x^2 -x + 2x - 2 = x^2 + x - 2

Numitorul comun este (x - 1)(x + 2)

(x + 2)^2 / (x - 1)(x + 2) - (x - 1)^2 / (x - 1)(x + 2) + 9 / (x - 1)(x + 2) =

= [(x^2 + 4x + 4) - (x^2 - 2x + 1) + 9] / (x - 1)(x + 2) =

= (x^2 + 4x + 4 - x^2 + 2x - 1 + 9] / (x - 1)(x + 2) =

= (6x + 12) / (x - 1)(x + 2) = 6(x + 2) / (x - 1)(x + 2) = 6 / (x - 1) = -6 / (1 - x)

-6 / (1 - x) : 3 / (1 - x) = -6 / (1 - x) * (1 - x) / 3 = - 2