1. 3x-10=x+70
+10 -x
2x=80
x=40
2. x+27+2x-39=180
3x-12=180
+12
3x = 180
x = 64
3. 2x ÷ 80=5x+44
- 2x -44
36= 3x
12=x
I'm not sure about the answer, but this is how I would do it, since 15% and $150 are the same based on the question. do let me know if it's right! :)