Question

Marque a alternativa CORRETA:

a) O(x+4). (x-4) = x² - 4

b) O(x-1)² = x² - 1

c) O(x + 2)² = x² + 4

d) O(x-5). (5+ x) = x² - 25​

Answer 1

a) Errada

$(x+4)*(x-4)\\x^{2} - 4x + 4x - 4^{2}\\x^{2} - 4^{2} = x^{2} - 16$

b) Errada

$(x-1)^{2}\\x^{2} - 2*x*1 + 1^{2}\\x^2 - 2x + 1$

c) Errada

$(x+2)^{2}\\x^{2} + 2*x*2 + 2^{2}\\x^{2} + 4x + 4$

d) Correta

$(x - 5)*(5+x)\\5x + x^{2} - 5^{2} - 5x\\x^{2} - 5^{2} = x^{2} - 25$