Answer:
x=4
Step-by-step explanation:
DE+EF=DF
(x-1)+(3x+3)=(5x-2)
x-1+3x+3=5x-2
4x+2=5x-2
-x=-4
1: 10x-5
2: 6.5w-3y
3: 15+3n
4: not sure
∠5=∠7=∠6=∠8=143°
∠4=∠2=∠1=37°
∠4=180-∠6=180-143=37°
-6x=-58