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

A)x + 5y + 6
B)x + 5y - 6
C)-x - 5y + 6
D)-x - 5y - 6

Question

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
 	
	A)x + 5y + 6
	B)x + 5y - 6
	C)-x - 5y + 6
	D)-x - 5y - 6

anonymous · Answer

@iGreen

mathstudent55 · Answer

Take the top equation and solve it for z.

mathstudent55 · Answer

x + 5y - z = 6

You want z by itself.
First, add 6 to both sides.
Then, add z to both sides.
What do you get?

igreen · Answer

@kellyconnelly  I wanna see how you really do it..so I'm gonna watch @mathstudent55

anonymous · Answer

x + 5y - z = 6
           +z   -6
x + 5y -6 = z

anonymous · Answer

this question is alot easier than I thought.. ahah

igreen · Answer

Nevermind..Lol.

anonymous · Answer

is B correct

igreen · Answer

I guess so..

anonymous · Answer

@mathstudent55

anonymous · Answer

i wanna double check hehhe

mathstudent55 · Answer

Great job. You have already done it.
z = x + 5y - 6
B is the answer, and you're done.

mathstudent55 · Answer

Not all math questions need to be hard. :-)