Question

2 – Determine o valor de x nas proporções:

a)x/6 = 32/48

b) 1/7 = x-6/49

c)2x+1/10 = 21/30

d)x-3/2x+1 = 4/5

Answer 1

Resposta:

a)x/6 = 32/48

$\frac{x}{6} = \frac{32}{48} \\ \\ 48x = 192 \\ \\ x = \frac{192}{48} \\ \\ x = 4$

b) 1/7 = x-6/49

$\frac{1}{7} = \frac{x - 6}{49} \\ \\ 7 \times (x - 6) = 49 \\ 7x - 42 = 49 \\ 7x - 42 - 49 = 0 \\ 7x - 91 = 0 \\ 7x = 91 \\ \\ x = \frac{91}{7} \\ \\ x = 13$

c)2x+1/10 = 21/30

$\frac{2x + 1}{10} = \frac{21}{30} \\ \\ 30 \times (2x + 1) = 210 \\ 60x + 30 = 210 \\ 60x + 30 - 210 = 0 \\ 60x - 180 = 0 \\ 60x = 180 \\ \\ x = \frac{180}{60} \\ \\ x = 3$

d)x-3/2x+1 = 4/5

$\frac{x - 3}{2x + 1} = \frac{4}{5} \\ \\ 5 \times (x - 3) = 4 \times (2x + 1) \\ 5x - 15 = 8x + 4 \\ 5x - 15 - 8x - 4 = 0 \\ - 3x - 19 = 0 \\ - 3x = 19 \times ( - 1) \\ 3x = - 19 \\ \\ x = \frac{19}{3}$