Question

Calculați : a) ( x - 1) ( x + 1) + (x + 1)² - ( x - 1) ²​

Answer 1

a)

(x-1)(x+1)+(x+1)²-(x-1)² =

= x²-1²+x²+2x+1²-(x²-2x+1²) =

= x²-1+x²+2x+1-x²+2x-1 =

= x²+4x-1

Answer 2

Răspuns: $\red{\underline{\bf x^2 +4x -1}}$

Explicație pas cu pas:

$\bf ( x - 1) \cdot ( x + 1) + (x + 1)^2 - ( x - 1)^2$

$\bf x^2 - 1 + (x^2+2x + 1) - ( x^2 -2x+ 1)$

$\bf \blue{x^2} - 1 + \blue{x^2}+\green{2x} + 1 - \blue{x^2} +\green{2x}- 1$

$\bf x^2 - 1 +4x$

$\red{\underline{\bf x^2 +4x -1}}$

Formule de calcul prescurtat folosite:

(a + b)² = a² + 2ab + b²

(a - b)² = a² – 2ab + b²

(a + b)(a - b) = a² - b²

==pav38==