Question

Qual o 2 e o 4 ? preciso das contas

Answer 1

$2 x^{2} -18x+28=0$

Δ = $9^{2} -4*14$

Δ = $9^{2} -56$

Δ = $81-56$

Δ = $25$

$x_{1,2} = \frac{-9\± \sqrt{25} }{2}$

$x_{1,2} = \frac{(-9)\±5}{2}$

$x' = \frac{(-9)+5}{2}$

$x'= \frac{-4}{2}$

$x' = -2$

$x'' = \frac{-9-5}{2}$

$x'' = \frac{-14}{2}$

$x'' = -7$

A = a menor  raiz ou seja -7
B = a maior raiz ou seja -2

$\frac{a}{b}$ ⇒ $\frac{-7}{-2}$ = 3,5

Letra A

4º) $2 x^{2} =-4+9x$

$2 x^{2} -9x=-4$

$2 x^{2} -9x+4=0$

Δ = $(-9)^{2} -4*2*4$

Δ = $(-9)^{2} - 32$

Δ = $81 - 32$

Δ = $49$

$x_{1,2} = \frac{9\± \sqrt{49}}{2*2}$

$x_{1,2} = \frac{ 9\±7}{2*2}$

$x' = \frac{9+7}{2*2}$

$x' = \frac{16}{2*2}$

$x' = \frac{8}{2}$

$x' = 4$

$x'' = \frac{9-7}{2*2}$

$x'' = \frac{2}{2*2}$

$x'' = \frac{1}{2}$

$x'' = 0,5$

$S = {[0,5; 4]}$

Letra C