We have the following:

A system of linear equations has infinite solutions when the graphs are exactly the same line.
for this to happen, on both sides the value of x must be equal:

replacing:
21.) is clue
I don't know the others I'm sorry...
Answer:
This is like quadratic equation you just say y=1x+-2 and then you get the answer
Just do a square and do 124/4= 31 and then to get the area you do length multiplied by length which is 31 X 31 which equals 961m squared.
Hope this helps
Step-by-step explanation:
4t-2k+5k-t
=3t -3k
= 3( t-k)