Question

Encontre o valor do variável :
A) x+4=12

B) x+x=15
_
3

C) 2x+0,5x=4,5

D) x+3x-0,5x=705

E) X+0,3x-x=84
_
7

F) x+3x-x=90
_
2

G)x+3+x=12
_ _ _
2 3 5

H)0,5x+2,5x+28=45

Answer 1

A) x + 4 = 12
x = 12 - 4
x = 8

B) x + x/3 = 15
3x/3 + x/3 = 45/3
3x + x = 45
4x = 45
x = 45/4

C) 2x + 0,5x = 4,5
2,5x = 4,5
x = 4,5 / 2,5
x =1,8

D) x + 3x - 0,5x = 705
1x + 3,5x = 705
4,5x = 705
x= 705/4,5

E) x/7 + 0,3x - x = 84
1x/7 + 2,1x/7 - 7x/7 = 588/7
1x + 2,1x - 7x = 588
3,1x - 7x = 588
- 3,9x = 588
- x = 588/3,9

F) x + 3x - x/2 = 90
2x/2 + 6x/2 - x/2 = 180/2
2x + 6x - x = 180
8x - x = 180
7x = 180
x = 180/7

G) x/2 + 3/3 + x/5 = 12
x/2 + 1 + x/5 =12
5x/10 + 10/10 + 2x/10 = 120/10
5x + 10 + 2x = 120
7x + 10 = 120
7x = 120 - 10
7x = 110
x = 110/7

H) 0,5x + 2,5x + 28 = 45
3x + 28 = 45
3x = 45 - 28
3x = 17
x = 17/3