Question

me ajudem atividade de matemática​

Answer 1

Resposta:

1)

$\frac{a}{b} = \frac{c}{d} \\ \\ bc = ad \\ \\ meios \: bc = 24 = > c = 8 \\ \\ 8b = 24 \\ \\ b = \frac{24}{8} \\ \\ b = 3$

2)

$\frac{x}{y} = \frac{8}{3} = > 3x = 8y = > 3x - 8y = 0 \\ \\ x + y = 132 \: \times ( - 3) \\3x - 8y = 0 \\ \\ 3x - 8y = 0 \\ - 3x - 3y = - 396 \\ \\ somando \\ \\ - 11y = - 396 \\ \\ y = \frac{ - 396}{ - 11} \\ \\ y = 36 \\ \\ 3x - 8(36) = 0 \\ 3x = 288 \\ \\ x = \frac{288}{3} \\ \\ x = 96$

3)

$a) \: \frac{3}{2} = \frac{9}{6} \\ \\ 2 \times 9 = 3 \times 6 \\ 18 = 18 \: \: verdade \: \: \\ proporcional \\ \\ b) \: \frac{4}{3} = \frac{3}{8} \\ \\ 3 \times 3 = 4 \times 8 \\ \\ 9 = 32 \: \: \: falso \: \:$

4)

$140 \: candidatos \\ 84 \: aprovados \\ \\ra zao \: = \frac{84}{014} = 0.6 \times 100 = 60\%$

5)

a)

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

b)

$\frac{0.8}{4} = \frac{x}{12} \\ \\ 4x = 9.6 \\ \\ x = \frac{9.6}{4} \\ \\ x = 2.4$

c)

$\frac{8}{y} = \frac{50}{12} \\ \\ 50y = 8 \times 12 \\ \\ 50y = 96 \\ \\ y = \frac{96}{50} \\ \\ y = 1.92$

d)

$\frac{ x }{4} = \frac{45}{5} \\ \\ 4 \times 45 = 5x \\ 180 = 5x \\ \\ x = \frac{180}{5} \\ \\ x = 36$

e)

$\frac{0.7}{7} = \frac{9}{x} \\ \\ 7 \times 9 = 0.7x \\ \\ 63 = 0.7x \\ \\ x = \frac{63}{0.7} \\ \\ x = 90$

f)

$\frac{1.2}{4} = \frac{x}{34} \\ \\ 4x = 40.8 \\ \\ x = \frac{40.8}{4} \\ \\ x = 10.2$

g)

$\frac{0.8}{0.2} = \frac{x}{2} \\ \\ 0.2x = 1.6 \\ \\ x = \frac{1.6}{0.2} \\ \\ x = 0.8$

h)

$\frac{64}{4} = \frac{x}{12} \\ \\ 4x = 12 \times6 4 \\ \\ 4x = 768 \\ \\ x = \frac{768}{4} \\ \\ x = 192$

i)

$1 = \frac{90}{y} \\ \\ 90 = 1 \times y \\ \\ y = 90$

Bons Estudos!