I am still learning, and am most likely incorrect.
I believe you remove the 3's since their not needed, and do this:
2x = 4x + 6 - (2x)
so then just ignore "x" and do this:
2 = 4 + 6 - 2
2 = 10 - 2
2 = 8
x = 8
700,000 is the answer...i think
1, 3 and 4.
1. 3,6>0,9
2. 3,6<4,725
3. 3,6>1,575
4. 3,6>0,54