A.) All parallelograms are trapezoids
Answer:

Step-by-step explanation:
For this case we need a line parallel to the plane x z and yz. And by definition of parallel we see that the intersection between the xz and yz plane is the z axis. And we can take the following unitary vector to construct the parametric equations:

Or any factor of u but for simplicity let's take the unitary vector.
Then the parametric equations are given by:



Where the point given 
And then since we have everything we can replace like this:




Answer:
This is an improper fraction so we need to make it a mix fraction.
Step-by-step explanation:
21/10 = 10/10+10/10+1/10
10/10=1
So your final answer will be 
4x-2y=8 ==> y=2x-4 (to better show you what I mean)
2 lines are parallel if they have the same slope (m the coefficient of x).
So y=mx + b // y =2x-4 means m=2 & y=mx + b, becomes y=2x + b.
Moreover they are telling us that this function passes by (-2,1), where -2 represents x & 1, represents y. To calculate b , replace x & y by their values:
y=2x+b ==> 1 = 2(- 2) + b==> 1 = -4 + b ==> b= 5. Finally the equation is
y=-2x+5