Respostas

2014-05-14T14:25:59-03:00
Responder esta equaçoes do 1º grau 

a) x/2 + 25=50
 x
----  + 25 = 50
 2

x + 50 = 100
-------------------- =    x + 50 = 100 ______ x = 100 - 50_____ x =50  
        2

5x/2 -25+10+5=50

5x
----- - 25 + 10 + 5 = 50
 2

5x 
----  -25 + 10 + 5 = 50
  2

5x - 50 + 20 + 10 = 100
---------------------------------- =  5x - 50 + 20 + 10 = 100_____5x -50 + 30 = 100
        2

5x - 20 = 100 _____ 5x = 100 + 20____5x = 120 ___x = 120/5___x = 24


c)5.(-x+2)=100
    - 5x + 10  = 100
    - 5x = 100 - 10
    - 5x = 90
       x = 90/-5
      x = - 18

d)x+3=18

 x + 3 = 18
x = 18 - 3
x = 15


e)x-3=18

x - 3 = 18
x = 18 + 3
x = 21

f)3x+3=18

3x + 3 = 18
3x = 18 - 3
3x = 15
x = 15/3
x = 5

g)2x+5-5x=1

2x + 5 - 5x = 1

2x - 5x + 5 = 1
- 3x + 5 = 1
-3x = 1 - 5
-3x = - 4
x = -4/-3
x =  + 4/3


h)-3x+10=2x+8+1

- 3x + 10 = 2x + 8 + 1
-3x + 10 =  2x + 9
-3x -2x + 10 = 9
-5x =9 - 10
-5x = -1
x = -1/-5
x = + 1/5


i)7(x-5)=3(x+1)

7(x-5) = 3(x+1)
7x - 35 = 3x + 3
7x - 3x - 35 = 3
7x - 3x = 3 + 35
4x = 38
x = 38/4

       38         19
x =  -----  =  --------- =      x= 19/2
        4           2

j)x/6+x/3=18-x/4

x         x                  x
---- + ------- =  18 -  --------
6         3                  4               mmc de 6,3,4 = 12

2x  +  4x = 216 - 3x
--------------------------------- =  
            12

2x  + 4x = 216 - 3x
6x = 216 - 3x
6x + 3x = 216
9x = 216
x = 216/9
x = 24