Question

Determine os valores de x e y, utilizando as propriedades das proporções:

Answer 1

Resposta:

Explicação passo a passo:

A)

x + y = 21

x/y = 2/5

5x = 2y

5x - 2y = 0

x + y = 21 .(2)

5x - 2y = 0

2x + 2y = 42

5x - 2y = 0 (+)

---------------

7x = 42

X = 42/7

X = 6

X + y = 21

6 + y = 21

y = 21 - 6

Y = 15

R.:

X = 6

Y = 15

__________

B)

x + y = 26

X/4 = y/9

9x = 4y

9x - 4y = 0

x + y = 26 .(4)

9x - 4y = 0

4x + 4y = 104

9x - 4y = 0 (+)

13x = 104

X = 104/13

x = 8

x + y = 26

8 + y = 26

y = 26 - 8

y = 18

R.:

x = 8

Y= 18

____________

C)

x - y = 8

x/y = 9/5

x - y = 8

5x = 9y

x - y = 8 .(-5)

5x - 9y = 0

- 5x + 5y = - 40

5x - 9y = 0

- 4y = - 40 (-1)

4y = 40

y = 40/4

y = 10

X - y = 8

X - 10 = 8

X = 8+10

X = 18

R.: x = 18; y = 10

Answer 2

Resposta:

Explicação passo a passo:

a)

x+y= 21

x/y= 2/5

x+y/y = 2+5/5

21/y= 7/5

y= 105/7

y= 15

x= 21-y

x= 21-15

x= 6

resp) x= 6    y= 15

--------------------------------------

b)

x+y= 26

x/4= y/9

x+y / 4+9 = x/4 = y/9

x+y/13 = x/4

26/13= x/4

2*4= x

x= 8

y= 26-x

y= 26-8

y= 18

resp)   x= 8      y= 18

----------------------------------------------

c)

x-y= 8

x/y= 9/5

x-y/y= 9-5/5

8/y = 4/5

y/8= 5/4

y= 8*5/4

y= 40/4

y= 10

x= 8+y

x= 8+10

x= 18

resp)   x= 18      y= 10