All the terms are like terms. When combined, their sum is zero (0).
Answer:

Step-by-step explanation:

-2x > -14 - 6
- 2x > - 20
x < 10
Yes you can with graphs and tables
Yes it’s a right angle because it has a 90 degree angle. In order for a triangle to be a right angle it needs to have one 90 degree angle. Hope this helps!