USE method of substution to solve the system of linear equatons.

4y-y=8
9x-2y=20

Solution? type order pair could some one show me how to get the answer on this

Question

USE method of substution to solve the system of linear equatons. 

4y-y=8
9x-2y=20

Solution? type order pair could some one show me how to get the answer on this

mathlegend · Answer

What I would do first is subtract the 4y from the first equation...

mathlegend · Answer

-y= -4y + 8

anonymous · Answer

4x-y=8
9x-2y=20

mathlegend · Answer

Then divide by -1

anonymous · Answer

use the top equation to solve for y and replace  that value for the y in the second equation

mathlegend · Answer

Now, since we solved for y... we can substitute it into the second equation as @emilie.li said.

mathlegend · Answer

9x-2(4x-8)=20

9x-8x+16=20

x+16=20
x= 4

mathlegend · Answer

That problem up there should say y=4x-8

anonymous · Answer

to be honest I don't know how to do any of this math homework

mathlegend · Answer

@Ne1977 do you understand how I solved for x?

mathlegend · Answer

@Ne1977 I need to know do you understand how I solved for 'x'? I will solve for 'y' if you understand.

anonymous · Answer

yes
I got 4, and 8

mathlegend · Answer

@Ne1977 you are so right! :)

mathlegend · Answer

Good job!