Tìm x biết: 2x.(x - 1/7) = 0; (3x - 1/4).(x + 1/5) = 0

bài 4 tìm x
e.2x.(x-1/7)=0
f.(3x-1/4).(x+1/5)=0
g.(2x-5).(3/2x+9).(0,3x-1,2)=0