Question

If you were to use the elimination method to solve the following system, choose the new system of equations that would result after the variable z is eliminated in the first and second equations, then the second and third equations.

x + y - 3z = -8
2x + 2y + z = 12
3x + y - z = -2


A. x + y = -8
3x + y = -2
B. x + y = -8
5x + 3y = 14
C. 7x + 7y = 28
3x + y = -2
D. 7x + 7y = 28
5x + 3y = 10

Answer 1

@texaschic101

Answer 2

@texaschic101 help me please

Answer 3

x + y - 3z = -8
2x + 2y + z = 12 --->(3)
------------
x + y - 3z = -8
6x + 6y + 3z = 36 (result of multiplying by 3)
-------------add
7x + 7y = 28


2x + 2y + z = 12
3x + y - z = -2
---------------add
5x + 3y = 10

solution is D