Question

f(x) = -x2 + 5x - 4 O mais rápido possível por favor

Answer 1

Oie, Td Bom?!

$f(x) = - x {}^{2} + 5x - 4$

$0 = - x {}^{2} + 5x - 4$

$- x {}^{2} + 5x - 4 = 0$

$x {}^{2} - 5x + 4 = 0$

$x {}^{2} - x - 4x + 4 = 0$

$x \: . \: (x - 1) - 4(x - 1) = 0$

$(x - 1) \: . \: (x - 4) = 0$

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$x - 1 = 0⇒x = 1$

$x - 4 = 0⇒x = 4$

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$S= \left \{x_{1} = 1 \: , \: x_{2} = 4 \right \}$

Att. Makaveli1996