Question

Calcule o valor de X

a) 3/15=x/6

b) 8/x=12/3

c) x+1/5=8/10

d) x-2/7=3/7

Answer 1

Calcule o valor de Xa) 3/15=x/6 

3      x
--- = -----   (só cruzar)
15     6

15(x) = 3(6)
15x =  18
x = 18/15   ( divide AMBOS por 3)
x = 6/5


 
b) 8/x=12/3

8        12
---- = ------  idem
x          3

12(x) = 8(3)
12x = 24
x = 24/12
x = 2


c) x+1/5=8/10

x + 1       8
------ = -------  idem
  5         10

10(x + 1) = 5(8)
10x + 10 = 40
10x = 40 - 10
10x = 30
x = 30/10
x = 3

d) x-2/7=3/7

x - 2       3
----- = ------  idem
 7          7

7(x - 2) = 7(3)
7x - 14 = 21
7x = 21 + 14
7x = 35
x = 35/7
x = 5