Question

Eliminate the “z” variable in the last two equations by finding opposite coefficients and adding. What is the resulting equation?

x + 3y + 2z = –16
2x – y + 2z = –15
2x – 2y – z = 1

4x – 3y = –14

4x + y = –14

6x + 5y = 13

6x – 5y = –13

Answer 1

simplify the last equation then add them... what do you get?

2x – y + 2z = –15
2*(2x – 2y – z = 1)

Answer 2

2x – y + 2z = –15
4x –4y – 2z = 2

add these two now...