Here's what I got for the first question.
Did you want answers for the second one? I couldn't read that part of the image very well, if you did.
Answer:
Step-by-step explanation:

21 has no 2 in it's prime factorization. So it can never end in 0, 2 , 4 , 6 , 8.
OR
Odd number raise to any number is always odd, Which does not include 2, 4, 6 , 8.
So
does not end with 0, 2, 4 , 6 , 8.
Answer:
Standard form is Ax+By=C
move the x-value to the left: 1/2x+y=4
1/2x+y=4
or multiply by 2x+2y=8
Step-by-step explanation:
I’m pretty sure the Answer is : 1016