- #1

chwala

Gold Member

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- Homework Statement
- See attached

- Relevant Equations
- linear equations

Find the solution here;

I will need to check which approach they used...probably some row- reduced echelon somewhere... anyway my approach;

##x+3y=4-kz##

##4x-2y=5+10z##

.................................

##4x+12y=16-4kz##

##4x-2y=5+10z##

.................................

##14y=11-4kz-10z##

.................................

From third equation,

##x+y+2z=1##

##y=1-2z-x##

##y=1-2z-(4-kz-3y)##

##-2y=-3-2z+kz## multiplying this by ##7##

.................................

Therefore,

##14y=11-4kz-10z##

##-14y=-21-14z+7zk##

...................................

subtracting we get,

##10=3kz-24z##

##10=z(3k-24)##

.................................

For no unique solution, we set

##3k-24=0##

##k=8##

Probably you may inform me which approach they used...just the form...otherwise, i can check this up later...

Arrrrgh i have seen it...using determinant! cheers guys.