Question

Trabalho de casa para segunda, não consigo fazer, mostre cálculos e use o teorema de tales por favor

Answer 1

A)

$=(-3)^{2}-4(1)(-10)$

$\frac{40}{16}=\frac{x}{18}\\\\16x = 40.18\\\\x=\frac{40.18}{16}\\\\x=45$

B)

$\frac{10}{15}=\frac{5}{x}\\\\10x = 15.5\\\\x=\frac{15.5}{10}\\\\x=7,5$

C)

$\frac{15}{12}=\frac{x}{10}\\\\12x = 15.10\\\\x=\frac{15.10}{12}\\\\x=12,5$

D)

$\frac{x+4}{x+1}=\frac{6}{x-1}\\\\(x+4).(x-1) = 6.(x+1)\\\\x^{2}-x+4x-4=6x+6\\\\x^{2}-x+4x-4-6x-6=0\\\\x^{2}-3x-10=0\\\\a=1, b=-3, c=-10$

Δ $=b^{2}-4ac$

Δ $=(-3)^{2}-4(1)(-10)$

Δ $=9+40$

Δ = 49

x = - b ± √Δ

           2a

$x'=\frac{-(-3)+\sqrt{49}}{2.1}\\\\x'=\frac{9+7}{2}\\\\x'=\frac{16}{2}\\\\x'=8$            $x''=\frac{-(-3)-\sqrt{49}}{2.1}\\\\x''=\frac{9-7}{2}\\\\x''=\frac{2}{2}\\\\x''=1$