Question

considere que r//s//t Nas figuras a seguir.​

Answer 1

Resposta:

a)

$\left\{\begin{array}{lI} a + b = 36 \\ \dfrac{a}{b} = \dfrac{4}{5} \end{array}\right$

$\left\{\begin{array}{lI} a= 36 - b \\ 5a = 4b \end{array}\right$

$\sf 5a = 4b \\5(36 -b) = 4b \\180 - 5b = 4b \\-5b - 4b = -180 \\-9b = -180 \\\\b = \dfrac{-\, 180}{-\, 9} \\\\b = 20$

$\sf a = 36 - b \\a = 36 - 20\\a = 16$

b)

$\sf \dfrac{5}{5x + 1} = \dfrac{3}{4x} \\\\5\times 4x = 3\times (5x + 1) \\20x = 15x + 3\\20x - 15x = 3\\5x = 3 \\\\x = \dfrac{3}{5} \\\\x = 0,6$

Explicação passo-a-passo:

método da substituição: