Question

Determine o valor do x nas proporções

Answer 1

a) 2 1

------ = ----

x + 1 5

1 . (x + 1) = 2 . 5

1x + 1 = 10

1x = 10 - 1

1x = 9

x = 9

---

1

x = 9

b) 5 2

------ = ---

x - 3 8

2 . (x - 3) = 5 . 8

2x - 6 = 40

2x = 40 + 6

2x = 46

x = 46

----

2

x = 23

c) 2 x + 1

--- = ------

9 18

9 . (x + 1) = 2 . 18

9x + 9 = 36

9x = 36 - 9

9x = 27

x = 27

----

9

x = 3

d) 5 4

--- = ------

x x - 1

4 . x = 5 . (x - 1)

4x = 5x - 5

4x - 5x = - 5

- x = - 5 . (-1)

x = 5

e) 4 1

-------- = ---

3x + 2 2

1 . (3x + 2) = 4 . 2

3x + 2 = 8

3x = 8 - 2

3x = 6

x = 6

---

3

x = 2

f) 3x x + 3

---- = -------

4 2

4 . (x + 3) = 3x . 2

4x + 12 = 3x . 2

4x - 3x = 2 - 12

x = - 10

g) x + 1 2

------- = ---

x + 2 3

2 . (x + 2) = 3 . (x + 1)

2x + 4 = 3x + 3

2x - 3x = 3 - 4

- x = - 1 . (-1)

x = 1