# solutions to system of equations

• Mar 16th 2011, 03:57 PM
Taurus3
solutions to system of equations
find all solutions to the following equations. How do I do this???

x1+2x+x3+x4=7
x1+2x2+2x3-x4=12
2x1+4x2+6x4=4
• Mar 16th 2011, 04:06 PM
pickslides
You have 4 unknowns and 3 equations which means your solution will not be unique. Are you aware of this?
• Mar 16th 2011, 06:10 PM
Taurus3
wait...so how do I solve it?
• Mar 16th 2011, 06:32 PM
pickslides
It can't be solved for a unique solution, before we go any further, take a look at this equation inparticular

Quote:

Originally Posted by Taurus3

x1+2x+x3+x4=7

Is it

$\displaystyle x_1+2x_2+x_3+x_4=7$

or

$\displaystyle x_1+x_2+x_3+x_4=7$

??
• Mar 17th 2011, 04:26 AM
HallsofIvy
The real question is, how have you learned to solve problems like these? There are a number of ways of solving such equations, ranging from fairly basic (eliminate variables by subtracting) to very sophisticated (row reduce the augmented matrix). Without more information, we cannot possibly know what woul be appropriate for you.