Question

1.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
Answer
6x + 5y = 13
4x – 3y = –14
6x – 5y = –13
4x + y = –14


2.The following system is solved by substitution. Which expression is substituted for z in the second and third equations?

x + 5y – z = 6
3x – y – 2z = 4
3x – 2y + 3z = 13
Answer
–x – 5y – 6
x + 5y – 6
–x – 5y + 6
x + 5y + 6

3.Solve the following system of equations.

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