Question

Aplique a regra de 3 e determine o valor de x
A-
7=49
5=x
B-
3=x
8=56
C-
4=x
9=36
d-
1+x=6
30=5

Answer 1

$a) \frac{7}{5} = \frac{49}{x} \\ \\ 7x=49*5 \\ \\ 7x=245 \\ x= \frac{245}{7} \\ \\ x=35 \\ \\ \\ \\ b) \frac{3}{8} = \frac{x}{56} \\ \\ 8x=3*56 \\ \\ 8x=168 \\ \\ x= \frac{168}{8} \\ \\ x=21 \\ \\ \\ \\ c) \frac{4}{9} = \frac{x}{36} \\ \\ 9x=4*36 \\ \\ 9x=144 \\ \\ x= \frac{144}{9} \\ \\ x=16$



$d) \frac{1+x}{30} = \frac{6}{5} \\ \\ (1+x)*5= 30*6 \\ \\ 5+5x=180 \\ \\ 5x=180-5 \\ \\ 5x=175 \\ \\ x= \frac{175}{5} \\ \\ x=35$

Answer 2

 
 

A- 
7=49
5=x 

7x = 225 ==> x= 225/7  

B-
3=x
8=56

8x = 168 ==> x = 168/8 ==> x = 21

C-
4=x
9=36

9x = 144 ==> x= 144/9  ==> x = 16

d-
1+x=6
30=5

5(1+x) = 180
 5 + 5x = 180
    5x = 180-5
    5x = 175
      x = 175/5
      x = 35