Answer :
[tex]0.4(2x+\frac{1}{2})=3[0.2x+(-2)]-4\ \ \ | omit\ brackets\\\\
0.8x+0.2=0.6x-6-4\\\\
0.8x+0.2=0.6x-10\ \ \ | subtract\ 0.6x\\\\
0.2x+0.2=-10\ \ \ | subtract\ 0.2\\\\
0.2x=-10.2\ \ \ | divide\ by\ 0.2\\\\
x=-51[/tex]