Question

Equação do primeiro grau

7x+5-x+8=31

27=3.(x+3)

16x+3(7x+8-9=6

6.(4x+2)+7(-5x+3)=6


12+(3x+6).(-7 )-5=70

Answer 1

7x + 5 - x + 8 = 31
7x - x + 5 + 8 = 31
6x + 13 = 31
6x = 31 - 13
6x = 18
x = 18/6
x = 3

27 = 3.(x + 3)
27 = 3x + 9
27 - 9 = 3x
18 = 3x
3x = 18
x = 18/3
x = 6

16x + 3.(7x + 8) - 9 = 6
16x + 21x + 24 - 9 = 6
37x + 15 = 6
37x = 6 - 15
37x = - 9
x = - 9/37

6.(4x+2) + 7.(-5x + 3) = 6
24x + 12 - 35x + 21 = 6
24x - 35x + 12 + 21 = 6
- 11x + 33 = 6
- 11x = 6 - 33
- 11x = - 27 (-1)
   11x = 27
x = 27/11

12 + (3x + 6).(-7 ) - 5 = 70
12 - 21x - 42 - 5 = 70
12 - 21x - 47 = 70
12 - 47 - 21x = 70
- 35 - 21x = 70
- 35 - 70 = 21x
- 105 = 21x
21x = - 105
x = - 105/21
x = - 5