Answer:
A) But if anyone thinks this they should go back to preschool
Step-by-step explanation:
On any other value of x you would take the numerators and denominators and multiply them across:

But, this literally does not make since considering the fact that you cannot divide any value by zero. Try it, it won't work. If we plug these into a trusty dusty calculator, we get this:

0*DOMAINERROR= You can't do it.
There are other reasons why you can't divide by zero, I would suggest looking them up on YT and learning about them.
I would answer A, but the person who wrote this question just wasn't focusing when they wrote the question.
Answer:
5/4
Step-by-step explanation:
4y = 5x Divide by 4
y = (5/4) x
To make y = kx from y = (5/4) x
k must be (5/4)
k = 5/4
Answer:
Solution (7,1)
Step-by-step explanation:
Use the elimination method
x + y=8
x - y=6
--------------Add
2x = 14
x = 7
Substitute x = 7 into x + y=8
7 + y=8
y = 8 - 7
y = 1
Solution (7,1)