please help i really don’t understand ( ignore the math on top )

Answer: x=2 DS=10 SE=10 DE=20
Step-by-step explanation:
[tex]7x-4=16-3x\\7x-4+3x=16-3x+3x\\10x-6=16\\10x-4+4=16+4\\10x=20\\[/tex]
Divide the equation by 10:
[tex]x=2[/tex]
Hence,
[tex]DS=(7)(2)-4\\DS=14-4\\DS=SE=10\\DE=DS+SE\\DE=10+10\\DE=20[/tex]