Question

Resolva as equações e determine quais delas pertencem ao conjunto in (com cálculo)
A)2x+6=20
B)2x-6=20
C)2x+6=-20
D)2x-6=-20
E)3x-8=-17
F)3x-8=17
G)3x+8=17
H)3x+8=-17

Answer 1

A)2x+6=20
   2x = 20 -6
   2x = 14
     x = 14/2
     x = 7

B)2x-6=20
   2x = 20 +6
   2x = 26
     x = 26/2
     x = 13

C)2x+6=-20
    2x = -20 -6
    2x = -26
      x = -26/2
      x = -13

D)2x-6=-20
    2x = -20 +6
    2x = -14
      x = -14/2
      x = -7

E)3x-8=-17
   3x = -17 +8
   3x = -9
     x = -9/3
     x = -3

F)3x-8=17
   3x = 17 +8
   3x = 25
     x = 25/3

G)3x+8=17
    3x = 17 -8
    3x = 9
      x = 9/3
      x = 3

H)3x+8=-17
    3x = -17 -8
    3x = -25
      x = -25/3