Answer:
1. Not a function: The x value is repeated.
2. brainly.com/question/5008648
3. Yes, passes vertical line test.
4. Yes, y values can be repeated.
Given,
The linear pair of the equation is,

Required
The solution of the linear equation.
Taking the equation first as,

Substituting the value of y in second equation then,

Substituting the value of x in first equation then,

Hence, the solution of the system is (1, -10).
I think the answer is B or C
Answer:
da answerr is six
if DF is 6 and all sides are equal in length the EF side is going to be 6 as well