Question

resolva as equações
a) 8a - (a + 3) = 11
b) 100x + 80 = 120x - 2.(20x - 150)
c) 2- (x - 3) - 4x = - 3x - 8

Answer 1

A) 8a - (a + 3) = 11
8a -a -3 = 11
7a - 3 = 11
7a = 11+3
7a = 14
a = 14/7
a=2

B) 100x + 80 = 120x - 2.(20x - 150)
100x + 80 = 120x -40x +300
100x +80 = 80x + 300
100x - 80x + 80 = 300
20x + 80 = 300
20x = 300 - 80
20x = 720
x = 720/20
x = 36

C) 2- (x - 3) - 4x = - 3x - 8
2 -x +3 -4x = -3x -8
2 -5x + 3 = -3x -8
-5x + 5 = -3x -8
-5x + 3x +5 = -8
-5x + 3x = -8 -5
-2x = -13 (.-1)
2x = 13
x = 13/2 ou
x= 6,5