matricies

[bailey07]

solve using matricies..

x-y+z=5
2x+3y-3z=0


i know that you must have 3 equations to solve for 3 variables, but i plugged numbers in and this is what i concluded:
3-(-2)+0=5
2(3)+3(-2)+0=0




therefore, x=3 y=-2 z=0


am i right or is there another way to do this

 

[stapel]

i know that you must have 3 equations to solve for 3 variables, but i plugged numbers in....

One must have three equations for three variables if the solutions are to have any chance of being unique, with x, y, and z each having some fixed value. Otherwise, there will be infinitely-many solutions, one or some of which may be easily guessable.

To solve this system properly (that is, completely), it would probably help to follow the instructions and use matrices, or else row operations on the system of equations, and thus arrive at the parametrised infinite solution.

Eliz.