Question

determine o valor de x em cada figura. ​

Answer 1

A)

$\frac{12}{9} = \frac{4}{x} \\ \\ 12x = 36 \\ x = \frac{36}{12} = 3$

B)

$\frac{x + 4}{5} = \frac{x + 2}{4} \\ \\ 5(x + 2) = 4(x + 4) \\ 5x + 10 = 4x + 16 \\ 5x - 4x = 16 - 10 \\ x = 6$

Answer 2

teorema de Tales

a ) -  

21 / 4 + x = 12 / 4

21 / 4 + x = 3

21 = 12 + 3x

3x = 9

x = 3

b ) -  

x + 4 + 5 / x + 2 + 4 = x + 4 / x + 2

x + 9 / x + 6 = x + 4 / x + 2

x² + 2x + 9x + 18 = x² + 4x + 6x + 24

x² + 11x + 18 = x² + 10x + 24

11x + 18 = 10x + 24

x = 6