Question

Mim ajude, não consigo responder​

Answer 1

1)

a) Acredito que seja um 6 acima do 5.

$\frac{x}{6} = \frac{25}{5} \\ x = 30$

$\frac{5}{y} = \frac{6}{16} \\ 6y = 80 \\ y = \frac{40}{3}$

b)

$\frac{9}{z} = \frac{3}{2} \\ 3z = 18 \\ z = \frac{18}{3} \\ z = 6$

$\frac{6}{12} = \frac{4}{y} \\ 6y = 48 \\ y = \frac{48}{6} \\ y = 8$

$\frac{9}{6} = \frac{x}{4} \\ 6x = 36 \\ x = \frac{36}{6} \\ x = 6$

2)

a)

$\frac{2x - 2}{3x + 1} = \frac{4}{7} \\ 12x + 4 = 14x - 14 \\ 12x - 14x = - 14 - 4 \\ - 2x = - 18 \\ x = 9$

b)

$\frac{3x}{x + 6} = \frac{x + 3}{x} \\ 3 {x}^{2} = {x}^{2} + 3x + 6x + 18 \\ 2 {x}^{2} - 9x - 18 = 0 \\ d = 81 - 4 \times 2 \times ( - 18) \\ d = 81 + 144 \\ d = 225 \\ \\ x1 = \frac{9 + 15}{4} = \frac{24}{4} = 6 \\ x2 = \frac{9 - 15}{4} = - \frac{6}{4} = - \frac{3}{2} (nao \: serve)$

3)

a)

$\frac{4}{16} = \frac{x}{12} \\ 16x = 48 \\ x = 3$

b)

$\frac{5 + 3}{5} = \frac{12}{x} \\ \frac{8}{5} = \frac{12}{x} \\ 8x = 60 \\ x = \frac{60}{8} \\ x = \frac{15}{2}$