Question

ASAP! 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 second equation.

2x + 5y – 2z = –1
x + 3y + z = –2
3x – 2y + 3z = –17

A. –y – 4z = 3
–11y = –11
B. 4x + 11y = –5
–11y = –11
C. –y = –5
6x + 7y = –11
D. 11y = 3
7y + 6z = –11

PLEASE ANSWER ASAP

Answer 1

so if the second equation has to have x isolated, start with that
x + 3y + z = –2 becomes
x=3y+z-2

you then want to substitute this into the other 2 equations

2(3y+z-2) + 5y – 2z = –1 => 6y+2z-4+5y-2z=-1
that becomes 11y=3

the thirs equation is
3(3y+z-2) – 2y + 3z = –17 => 9y+3z-6-2y+3z=-17
that becomes 7y+6z=-11
i believe that your answer is D