Substitute x and y into A, B, or C to find z?

Question

A. 5x + 3y + 2z = 2
B. 2x + y – z = 5
C. x + 4y + 2z = 16

Use A and B to eliminate z.
A. 5x + 3y + 2z = 2 A.
B. [2x + y – z = 5]2 B. .
AB. .

Use B and C to eliminate z.
B. [2x + y – z = 5]2 B.
C. x + 4y + 2z = 16 C. .
BC. .


Solve AB and BC to find x and y.
AB. . AB.
BC. . BC.

AB. .



Substitute x and y into A, B, or C to find z.
B. 2x + y – z = 5
2( ) + ( ) – z = 5


SOLUTION: (-2, 6, -3)

Answer 1

5x+3y+2z = 2

5(-2)+3(6)+2(-3)=-10+18-6=2

2x+y-z =5

2(-2)+6 -(-3)=-4+6+3 = 5

x+4y+2z = 16

(-2)+4(6)+2(-3)= -2+24-6= 16

(-2,6,-3) is the correct solution

x=-2, y=6, z=-3