Question

A) Os coeficientes de a, b e c

B) f(0), f(1), f(-2) e f(1/2).

C) Calcule X e R para que f(x) = 3

Answer 1

Explicação passo-a-passo:

$f(x) = x {}^{2} - 6x + 8$

$a)a = 1 \: \: \: b = - 6 \: \: \: \: \: \: \: \: c = 8$

$b)f(0) = 0 {}^{2} - 6 \times 0 + 8 = 0 - 0 + 8 = 8$

$f(1) = 1 {}^{2} - 6 \times 1 + 8 = 1 - 6 + 8 = 3$

$f( - 2) = ( - 2) {}^{2} - 6 \times - 2 + 8 = 4 + 12 + 8 = 24$

$f( \frac{1}{2} ) = ( \frac{1}{2} ) {}^{2} - 6 \times \frac{1}{2} + 8 = \frac{1}{4} - \frac{6}{2} + 8 = mmc = 4$

$\frac{1 - 12 + 32}{4} = \frac{21}{4}$

$c)x{}^{2} - 6x +8 = 3$

$x {}^{2} - 6x + 8 - 3 = 0$

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

$a = 1 \: \: \: \: b = - 6 \: \: \: \: c = 5$

$delta = b {}^{2} - 4ac$

$delta = ( - 6) {}^{2} - 4.1.5 = 36 - 20 = 16$

$\sqrt{16} = 4$

$x1 = \frac{ - ( - 6) + 4}{2.1} = \frac{6 + 4}{2} = \frac{10}{2} = 5$

$x2 = \frac{ - ( - 6) - 4}{2.1} = \frac{6 - 4}{2} = \frac{2}{2} = 1$