Tìm x, biết: 2- x:3/4 =1/2

A) 2-x:3/4=1/2
B)(3x+2) (x-3/2)=0
C)1 - 1/1.2 - 1/2.3 - 1/3.4 -...- 1/19.20 + 3x = 1/4
D)(x^2+3) (3-5x)=0