Respostas

2013-11-30T16:11:49-02:00
20 - 5(1 - X) + (2X - 3) -1=0
20 -5 + 5X +2X - 3 - 1 = 0

VC  pode juntar os termos semelhantes

5x +2x +  20 - 5- 3 - 1 = 0
adicione os termons semelhantes

7X + 11 = 0
7X = -11
X = -11/7

OU X ≡ 1,5714...
1 5 1
2013-11-30T18:18:10-02:00
20 - 5 ( 1 - x ) + ( 2x - 3 ) - 1 = 0
20 - 5 + 5x + 2x - 3 - 1 = 0
5x + 2x + 20 - 9 = 0
7x + 11 = 0
x =  - 11/7
1 5 1