Answer:
Reflexive
Step-by-step explanation:
Because C and D are right angles. That’s def of perpendicular. I’m not sure about the vertical angles but it’s shown in the proof
I believe the answer would be x20. Between the two parentheses there's a multiplication symbol. So you would just pretend that the parentheses aren't there cause the variable(s) (x) is/are like terms. So you would just multiply 10 times 2 and put out the x back in front of it