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
Răspuns: [tex]\red{\underline{\bf x^2 +4x -1}}[/tex]
Explicație pas cu pas:
[tex]\bf ( x - 1) \cdot ( x + 1) + (x + 1)^2 - ( x - 1)^2[/tex]
[tex]\bf x^2 - 1 + (x^2+2x + 1) - ( x^2 -2x+ 1)[/tex]
[tex]\bf \blue{x^2} - 1 + \blue{x^2}+\green{2x} + 1 - \blue{x^2} +\green{2x}- 1[/tex]
[tex]\bf x^2 - 1 +4x[/tex]
[tex]\red{\underline{\bf x^2 +4x -1}}[/tex]
Formule de calcul prescurtat folosite:
(a + b)² = a² + 2ab + b²
(a - b)² = a² – 2ab + b²
(a + b)(a - b) = a² - b²
==pav38==
