2(x+7) + x=20
(2)(x) + (2)(7) + x=20 Distribute
2x+14 + x =20
(2x+x) + (14) =20 Combine Like Terms
3x+14=20
- 14 -14 Subtract 14 from both sides
3x = 6
3x/3 6/3 Divide Both Sides by 3
x = 2
Let me know if you still don't understand
1. C
2.D
3.A
4.B
Hope this helps!
If you're using a coordinate plane, I think it makes a trapezoid
