Question

Calcule o valor de x nas proporções:

A) 5 = x
3 21


B) 7 = 3
x 27

C) 8 = 2
32 x

D) 5 = 15
8 x


OBS: sao frações

Answer 1

Explicação passo-a-passo:

a)

$\sf \dfrac{5}{3}=\dfrac{x}{21}$

$\sf 3x=5\cdot21$

$\sf 3x=105$

$\sf x=\dfrac{105}{3}$

$\sf \red{x=35}$

b)

$\sf \dfrac{7}{x}=\dfrac{3}{27}$

$\sf 3x=7\cdot27$

$\sf 3x=189$

$\sf x=\dfrac{189}{3}$

$\sf \red{x=63}$

c)

$\sf \dfrac{8}{32}=\dfrac{2}{x}$

$\sf 8x=32\cdot21$

$\sf 8x=64$

$\sf x=\dfrac{64}{8}$

$\sf \red{x=8}$

d)

$\sf \dfrac{5}{8}=\dfrac{15}{x}$

$\sf 5x=8\cdot15$

$\sf 5x=120$

$\sf x=\dfrac{120}{5}$

$\sf \red{x=24}$

Answer 2

Oie, Td Bom?!

A)

5/3 = x/21

5 . 21 = 3x

105 = 3x

3x = 105

x = 105/3

x = 35

B)

7/x = 3/27

7/x = [3 ÷ 3]/[27 ÷ 3]

7/x = 1/9

7 . 9 = 1x

63 = x

x = 63

C)

8/32 = 2/x

[8 ÷ 8]/[32 ÷ 8] = 2/x

1/4 = 2/x

1x = 2 . 4

x = 8

D)

5/8 = 15/x

5x = 15 . 8

5x = 120

x = 120/5

x = 24

Att. Makaveli1996