Question

resolva as seguintes proporcoes ;
a) x/5  = 21/35
b)10/7 = 50/x
c)1/7  =x-6/49
d)5x+3 /10 = -21/30

Answer 1

a)
x = 21
5    35
35x = 21 * 5
35x = 105
x = 105 ÷ 35
x = 3


b)
10 = 50
 7      x
10x = 50 * 7
10x = 350
x = 350 ÷ 10
x = 35

c)
1 = x -  6  
7         49
x = 1 +  6      
      7    49

mmc (7, 49) = 49     

x = 7 +  6
        49
x = 13
      49

d)
5x +  3  = - 21
       10       30
5x = - 21 -  3   
          30   10

mmc (10, 30) = 30

5x = - 21 - 9
           30
5x = - 30
          30
5x = - 1
x = - 1 ÷ 5
x = - 0,2