SOLUTION: 3x-4y=8 y= 3/4x-2 I got 3x-4{3/4x-2}=8 3x-3x=16 I have no varible left? Is that right?

Algebra ->  Systems-of-equations -> SOLUTION: 3x-4y=8 y= 3/4x-2 I got 3x-4{3/4x-2}=8 3x-3x=16 I have no varible left? Is that right?       Log On


   



Question 36432: 3x-4y=8
y= 3/4x-2
I got
3x-4{3/4x-2}=8
3x-3x=16
I have no varible left? Is that right?

Found 2 solutions by checkley71, Earlsdon:
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
ARE YOU SURE YOU COPIED THE PROBLEM CORRECTLY.
COULD IT BE Y=(3/4X)-2??????

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You are right in saying that you have no variable left, but finish up the problem then you can interpret the result.
3x-4%28%283%2F4%29x-2%29+=+8
3x-3x%2B8+=+8
8+=+8 No variable but the equation is valid (8 = 8).
This means that all values of x and y that satisfy the one equation will also satisfy the second equation...why?
Well, this is easier to see if you get both equations into the slope-intercept form:
1) 3x-4y+=+8 Subtract 3x from both sides.
-4y+=+-3x+%2B+8 Divide both sides by -4.
1) y+=+%283%2F4%29x+-+2
2) y+=+%283%2F4%29x+-+2
You can see immediately that the two equations represent the same line so any point that lies on the first line will also lie on the second line.