# Thread: Graphing System of Equations w/4 variables...

1. ## Graphing System of Equations w/4 variables...

I am helping my son. We need to graph this sytem of equations:

a+b+c+d = 7.11

abcd = 7.11

Neither one of us has any clue how to begin graphing equations with four variables. His teacher mentioned using the Quadratic Method, but I don't see how. Can anyone help?

Thanks!
Kim

2. Originally Posted by Profitweb
I am helping my son. We need to graph this sytem of equations:

a+b+c+d = 7.11

abcd = 7.11

Neither one of us has any clue how to begin graphing equations with four variables. His teacher mentioned using the Quadratic Method, but I don't see how. Can anyone help?

Thanks!
Kim
This is ALMOST a double post! Hmmm....

Anyway, you need one coordinate axis for each unknown variable. Since you have 4 unknowns you will need 4 coordinate axes. As this is one more dimension than we live in, you'll have a little trouble finding the graph paper!

Going back to the other post what the teacher was suggesting was to convert the system to
x + y = 7.11
x*y = 7.11
and solving THIS system graphically. (But as I showed in the other post this doesn't give a real solution for all a, b, c, and d.)

-Dan