Question

Calcule o valor de x na proporções
A) 2x/15=6/9
B) X/6=x+3/15
C) X-2/X=12/20
D) X-3/X=4/5
E)X-3/18=1/2
F) 2/1=15-X/X
G)6/10=X/X+2

Answer 1

Explicação passo-a-passo:

$a) \frac{2x}{15} = \frac{6}{9} \\ \\ \frac{2x}{15} = \frac{2}{3} \\ \\ 2x \times 3 = 2 \times 15 \\ 6x = 30 \\ x = \frac{30}{6} \\ \\ x = 5$

$b) \frac{x}{6} = \frac{x + 3}{15} \\ \\ 15x = 6(x + 3) \\ 15x = 6x + 18 \\ 15x - 6x = 18 \\ 9x = 18 \\ x = \frac{18}{9} \\ \\ x = 2$

$c) \frac{x - 2}{x} = \frac{12}{20} \\ \\ \frac{x - 2}{x} = \frac{3}{5} \\ \\ 5(x - 2) = 3x \\ 5x - 10 = 3x \\ 5x - 3x = 10 \\ 2x = 10 \\ x = \frac{10}{2} \\ \\ x = 5$

$d) \frac{x - 3}{x} = \frac{4}{5} \\ \\ 5(x - 3) = 4x \\ 5x - 15 = 4x \\ 5x - 4x = 15 \\ x = 15$

$e) \frac{x - 3}{18} = \frac{1}{2} \\ \\ 2(x - 3) = 18 \\ 2x - 6 = 18 \\ 2x = 18 + 6 \\ 2x = 24 \\ x = \frac{24}{2} \\ \\ x = 12$

$f) \frac{2}{1} = \frac{15 - x}{x} \\ \\ 2x = 15 - x \\ 2x + x = 15 \\ 3x = 15 \\ x = \frac{15}{3} \\ \\ x = 5$

$g) \frac{6}{10} = \frac{x}{x + 2} \\ \\ \frac{3}{5} = \frac{x}{x + 2} \\ \\ 3(x + 2) = 5x \\ 3x + 6 = 5x \\ 3x - 5x = - 6 \\ - 2x = - 6 \\ x = \frac{ - 6}{ - 2} \\ \\ x = 3$