Question

3) Quais os zeros da função f(x) = x2 -5x + 6?
(A) -2 e 3
(B) 2 e-3
(C) -2 0-3
(D) 2 e 3
(E) 0 e 1​

Answer 1

Oie, Td Bom?

■ Resposta: Opção D.

$f(x) = x {}^{2} - 5x + 6$

$0 = x {}^{2} - 5x + 6$

$x {}^{2} - 5x + 6 = 0$

$x {}^{2} - 2x - 3x + 6 = 0$

$x \: . \: (x - 2) - 3(x - 2) = 0$

$(x - 2) \: . \: (x - 3) = 0$

• $x - 2 = 0⇒x = 2$

• $x - 3 = 0⇒x = 3$

$S = \left \{2 \: , \: 3 \right \}$

Att. Makaveli1996

Answer 2

Alternativa D) 2 e 3

$f(x) = {x}^{2} - 5x + 6 \\ 0 = {x}^{2} - 5x + 6 \\ {x}^{2} - 5x + 6 = 0 \\ {x}^{2} - 2x - 3x + 6 = 0 \\ x \times (x - 2) - 3(x - 2) = 0 \\ (x - 2) \times (x - 3) = 0 \\ x - 2 = 0 \\ x - 3 = 0 \\ x = 2 \\ x = 3 \\ x1 = 2 \: \: \: \: \: x2 = 3$