5 . (x + 1) = 0

Tìm x:
a) 1/3x + 2/5 . (x + 1) = 0
b) 50%x + 2/3x = x + 4
c) 1/3x + 2/5 . (- x + 1) = 0
d) x + 2/3x = - x + 1