Substitution method (algebra 2) please please help

If you were to use the substitution method to solve the following system, choose the new system of equations that would result if x was isolated in the first equation.

x – 6y + 3z = 0
2x – 5y + 8z = 7
x + 7y – 4z = 13

A.) –17y + 14z = 7
y – z = 13

B.) 7y + 2z = 7
13y – 7z = 13

C.) 13y + 7z = –13
–19y + 16z = –19

D.) y – z = –13
9y + 0z = –19

I know this question looks really long but I have 10 more of these problems to do and I have no idea how to do them. If you could please help me I'd really appreciate it and I will pick a best answer to give 10 points to. Thank you so much in advance!!!

If you were to use the substitution method to solve the following system,
choose the new system of equations that would result
if x was isolated in the first equation.

x - 6y + 3z = 0
2x - 5y + 8z = 7
x + 7y - 4z = 13

x = 6y - 3z
Answer:
B.)
7y + 2z = 7
13y - 7z = 13